Weekly Quizzes - Weeks 3, 4, 5
A 52 year old man has experienced increasing fatigue for the past 6 months. On physical examination, he has a palpable spleen tip. Laboratory studies show a WBC count of 189,000/µL. The peripheral blood smear shows many mature and immature myeloid cells. Cytogenetic analysis of cells obtained via bone marrow aspiration reveals a t (9:22) translocation to be present. This translocation leads to formation of a hybrid gene that greatly increases tyrosine kinase activity. Which of the following genes is most likely translocated to cause these findings? (A) ABL (B) NF-1 (C) p53 (D) RAS (E) RB
A. ABL
A 50 yr old man has a 2 year history of angina pectoris that occurs when he exercises. His blood pressure and pulse are normal. Coronary angiography shows 75% narrowing of the left anterior descending artery. Which of the following cell types was the initial target in the development of his lesion? A. Endothelial cells B. Fibroblasts C. Lymphocytes D. Platelets E. Smooth muscle cells
A. Endothelial cells
A 76 year old woman has experienced decreased visual acuity in her left eye for the past week. She also has had a left-sided headache during this time. On physical examination, her temperature is 37.4°C with blood pressure 135/85 mm Hg. There is a tender cord-like area palpable over her forehead just above and posterior to her left eye. Laboratory studies show an elevated erythrocyte sedimentation rate of 99 mm/hr. Her condition improves with corticosteroid therapy. Which of the following is the most likely diagnosis? (A) Giant cell temporal arteritis (B) Polyarteritis nodosa (C) Systemic lupus erythematosus (D) Thromboangiitis obliterans (E) Wegener's granulomatosis
A. Giant cell temporal arteritis
You are counseling a patient who is concerned that he was exposed to an HIV-infected sexual partner 2 weeks ago. The patient is asymptomatic. Which of the following tests is most likely to indicate the presence of infection at this early time point? A. HIV viral load by PCR B. HIV serology C. CD4 count D. Serum LDH
A. HIV viral load by PCR
Which of the following factors generally favors tolerance to an antigen and not stimulation of an immune response? (A) High doses of antigen (B) Short-lived persistence of antigen (C) Cutaneous portal of entry (D) Presence of adjuvant (E) Costimulator expression on antigen-presenting cells
A. High doses of antigen
The T cell receptor (TCR) complex differs from an immunoglobulin molecule in which one of the following ways? (A) On average, a TCR binds antigen with much lower affinity than does an Ig molecule. (B) The TCR can serve as a lymphocyte antigen receptor, but an Ig molecule cannot. (C) Only the TCR can bind soluble antigen directly. (D) The TCRs expressed by one clone of T cells can undergo changes in constant region structure after cellular activation, whereas Ig molecules expressed by one clone of B cells do not. (E) The TCR polypeptide chains have short cytoplasmic tails and rely on associated proteins for signaling functions, whereas membrane Ig receptors are competent signaling molecules on their own.
A. On average, a TCR binds antigen with much lower affinity than does an Ig molecule
In which of the following disorders is the underlying pathogenic mechanism not due to antibody-mediated damage to cells or tissues? (A) Pernicious anemia (B) Autoimmune hemolytic anemia (C) Pemphigus vulgaris (D) Acute rheumatic fever (E) Hyperacute allograft rejection
A. Pernicious anemia
The very rapid response to a second allogeneic graft is (A) Specific for antigens of the major histocompatibility complex (MHC) (B) Dependent on minor histocompatibility antigens (C) Transferred by macrophages to a naïve recipient (D) Transferred by platelets (E) Transferred by IgA
A. Specific for antigens of the MHC
Cytolytic viruses are typically: A. Cleared by cell-mediated immunity B. Non-enveloped C. DNA viruses D. Released apically
B. Non-enveloped
Which of the following statements regarding neuraminidase inhibitors is true? A. The are only effective against Influenza A B. They work by blocking release of visions from infected cells C. They are most effective when given on or after day 5 of illness D. Confusion and anxiety are common side effects
B. They work by blocking release of visions from infected cells
Which of the following is implicated in the pathogenesis of Reye's syndrome? A. Primary pneumonia B. Secondary pneumonia C. Asprin D. Acetaminophen
C. Aspirin
Which of the following statements about the molecules B7-1 and B7-2 is false? (A) B7-1 and B7-2 expression on antigen-presenting cells (APCs) is upregulated by the presence of "danger" signals, such as lipopolysaccharide, as well as cytokines, such as interferon (IFN)-γ. (B) B7-1 and B7-2 are expressed at low levels on some resting APCs. (C) B7-1 and B7-2 bind to CTLA-4 on activated T cells and provide signals for continued T cell activation. (D) B7-1 and B7-2 bind to CD28 on T cells and provide "second signals" for naive T cell activation. (E) Activated helper T cells can induce expression of B7-1 and B7-2 on APCs via CD40L binding to CD40.
C. B7-1 and B7-2 bind to CTLA-4 on activated T cells and provide signals for continued T cell activation
The spherule is the tissue form of infection due to which thermally dimorphic fungus? (A) Histoplasma capsulatum (B) Blastomyces dermatitidis (C) Coccidioides immitis (D) Sporothrix schenckii (E) Paracoccidioides brasiliensis
C. Coccidioides immitis
Which of the following thermally dimorphic fungi is endemic in the southwestern United States? (A) Histoplasma capsulatum (B) Blastomyces dermatitidis (C) Coccidioides immitis (D) Sporothrix schenckii (E) Paracoccidioides brasiliensis
C. Coccidioides immitis
A 61 yr old man has had lower leg swelling and pitting edema to the knees w/ prominent jugular venous dissension to the level of the mandible. He also complains of dyspnea after walking form his bedroom to his kitchen. Based on the appearance of the liver seen here, which of the following underlying conditions is likely to be present? A. Chronic renal failure B. Common bile duct obstruction C. Congestive heart failure D. Portal vein thrombosis E. Thrombocytopenia
C. Congestive heart failure
Chronic mucocutaneous candidiasis is characterized clinically by severe and recurrent skin and mucosal infections. The underlying immune defects include several genetic mutations resulting in (A) Altered macrophage phagocytosis (B) Impaired respiratory burst of neutrophils (C) Defective Th-1 mediated immunity (D) Low IgG levels
C. Defective Th-1 mediated immunity
A 12 yr old boy presents w/ a history of easy bruising and recurrent bleeding into his knee joints. He required a blood transfusion following extraction of a tooth when he was 9 yrs old. Laboratory results show a APTT of 108 seconds w/ a control of 32 seconds, normal PT, and normal bleeding time. The patient has which of the following deficiencies? A. Factor II B. Factor VII C. Factor VIII D. Factor XII E. vonWillebrand factor
C. Factor VIII
Which of the following statements about interferons is true? A. Interferons kill viruses directly B. Interferons inhibit viral DNA polymerization C. Interferons protect uninfected cells from subsequent viral infection D. Interferons are released primarily by virally infected neurons
C. Interferons protect uninfected cells from subsequent viral infection
Which of the following statements regarding positive and negative selection of T cells is false? (A) Thymic epithelial cells present self-peptide-MHC to developing T cells undergoing the selection process. (B) T cells that do not recognize self-peptide-MHC die by neglect. (C) T cells that bind too strongly to self-peptide-MHC die by Fas ligand-mediated apoptosis. (D) During positive selection, developing T cells express higher levels of anti-apoptotic proteins such as bcl-2. (E) A breakdown in negative selection may result in the development of some autoimmune diseases.
C. T cells that bind too strongly to self-peptide-MHC die by Fas ligand-mediated apoptosis.
Which of the following patients is particularly susceptible to infection with Streptococcus pneumoniae, an encapsulated bacterium? (A) A 23 year old man with malaise, rash, and diffuse lymphadenopathy consistent with early infection with human immunodeficiency virus (B) A 54 year old woman receiving local corticosteroid injections for knee pain (C) A 35 year old man with Hodgkin's disease and a deficient delayed-type hypersensitivity (DTH) response to Candida antigen (D) A 6 year old boy with sickle cell anemia who had a splenectomy (E) A 77 year old woman on chronic renal dialysis and a strict low-protein diet
D. A 6 yr old boy w/ sickle cell anemia who had a splenectomy.
Which of the following fungi grow in culture as hyphae with frequent septa and acute angle branching? (A) Candida albicans (B) Candida glabrata (C) Rhizopus oryzae (D) Aspergillus fumigatus (E) Cryptococcus neoformans
D. Aspergillus fumigatus
Which of the following is a common cause of hypersensitivity diseases? (A) Failure of lymphocyte maturation (B) Treatment with corticosteroids (C) Disseminated cancer (D) Failure of self-tolerance (E) Malnutrition
D. Failure of self-tolerance
After running multiple repeat assays using a control sample of known value on a single laboratory instrument, you observe that the data points are very close in value to each other, but are not close to the true value known in the sample. This test can be said to have (A) Good accuracy but poor precision (B) Good coefficient of variation but poor standard deviation (C) Good negative predictive value but poor precision (D) Good precision but poor accuracy (E) Good precision but poor positive predictive value
D. Good precision but poor accuracy
Which of the following statements is true about thrush (oral mucosal candidiasis) in newborns? (A) Oral thrush is a sign of immune deficiency and should prompt extensive evaluation of immune function. (B) The physiological similarities between fungal and mammalian cells make antifungal therapy very toxic, and antifungal agents should not be used in children less than 12 months old. (C) Oral thrush in babies should be treated given the likelihood that is will develop into a systemic infection. (D) Oral thrush is a tissue invasive process and therefore can be uncomfortable for the baby.
D. Oral thrush is a tissue invasive process and therefore can be uncomfortable for the baby
All of the following thermally dimorphic fungi typically enter the human host through the respiratory route except (A) Histoplasma capsulatum (B) Blastomyces dermatitidis (C) Coccidioides immitis (D) Sporothrix schenckii (E) Paracoccidioides brasiliensis
D. Sporothrix schenckii
All of the following are structural genes of HIV except: A. Gag B. Pol C. Env D. Umb
D. Umb
Which of the following allogeneic grafts does not require immunosuppression? (A) Kidney (B) Heart (C) Liver (D) Bone Marrow (E) Cartilage
E. Cartilage
Which of the following events does not occur within germinal centers? (A) Somatic mutation of Ig V genes (B) Generation of memory B cells (C) B cell proliferation (D) Affinity maturation (E) Ig gene V(D)J recombination
E. Ig gene VDJ recombination
Treatment of antibodies with the enzyme papain under conditions of limited proteolysis results in hinge-region cleavage, yielding monovalent antigen-binding Fab fragments that lack a constant region. Which effector function of antibodies would Fab fragments be able to perform? (A) Complement pathway activation (B) Antibody-dependent cell-mediated cytotoxicity (C) Opsonization (D) Antigen cross-linking and precipitation (E) Microbe neutralization
E. Microbe neutralization
Which of the following is most commonly associated w/ interstitial pneumonia in pregnant women and immunocompromised patients? A. HHV-7 B. HHV-8 C. HSV-1 D. HSV-2 E. VZV
E. VZV
The clinical laboratory plays an essential role in health care. It has been estimated that 70% of all medical decisions are based on laboratory results. The Institute of Medicine states that laboratory costs account for approximately what percentage of total healthcare dollars? (A) 1-5% (B) 5-10% (C) 10-20% (D) 20-30% (E) >30%
A. 1-5%
The basic Ig unit is composed of: (A) 2 identical heavy and 2 identical light chains (B) 2 identical heavy and 2 different light chains (C) 2 different heavy and 2 identical light chains (D) 2 different heavy and 2 different light chains (E) Non-covalently bound polypeptide chains
A. 2 identical heavy and 2 identical light chains
A 67 year old man has noted a chronic cough for the past three months. Physical examination reveals a mild stridor on inspiration over the right lung. A chest radiograph shows a 5 cm right hilar lung mass, and a biopsy specimen of the mass shows the lesion below. No other abnormalities are seen on chest CT. Additional studies are done and the staging of this neoplasm is denoted as T2N1M1. Based only on the information provided, which of the following statements is most accurate? (A) A CT scan of the brain must show metastasis. (B) Serum chemistry shows an elevated corticotrophin level. (C) The cancer is poorly differentiated. (D) The mass had infiltrated the diaphragm. (E) The tumor is obstructing the left mainstem bronchus.
A. A CT scan of the brain must show metastasis.
A thin section of liver viewed w/ an electron microscope shows viral particles in the nuclei of hepatocytes. What kind of virus might this be? A. A DNA virus like adenovirus B. An RNA virus like hepatitis E virus C. An enveloped virus like SARS coronavirus D. A naked virus like poliovirus E. A big virus like E.coli
A. A DNA virus like adenovirus
Most T lymphocytes have a dual specificity for which one of the following pairs of molecules? (A) A particular allelic form of a major histocompatibility complex (MHC) molecule and a peptide bound to the MHC molecule (B) Both MHC class I and class II molecules (C) Both peptide and glycolipid antigens (D) Both soluble peptides and peptide-MHC complexes (E) MHC molecules and CD4 or CD8
A. A particular allelic form of a MHC molecule and a peptide bound to the MHC molecule
During a routine health maintenance examination of a 40 year old man a stool guaiac test result was positive (occult blood in the stool). A follow-up sigmoidoscopy showed a 1.5 cm circumscribed, pedunculated mass on a short stalk, located in the upper rectum (shown below). Which of the following terms best describes this lesion? (A) Adenoma (B) Dysplasia (C) Hamartoma (D) Melanoma (E) Sarcoma
A. Adenoma
Neonates, elderly persons, and otherwise immunocompromised patients are particularly susceptible to infections with Listeria monocytogenes. These patients typically have fever and chills, often progressing to hypotension and septic shock. In healthy individuals, however, such intracellular microbes are usually effectively phagocytosed and killed by macrophages, which become activated via (A) CD40L-CD40 interactions between activated T helper cells and macrophages (B) CD28-B7 interactions between activated T cells and macrophages (C) Fas ligand-Fas interactions between activated cytotoxic T lymphocytes and macrophages (D) TCR-MHC class II interactions between activated T helper cells and macrophages (E) LFA-1-ICAM-1 interactions between activated T cells and macrophages
A. CD40L-CD40 interactions between activated T helper cells and macrophages
A clinical study involves patients diagnosed with carcinoma and whose tumor stage is T4N1M1. The patients' survival rate 5 years from the time of diagnosis is less than 50%, regardless of therapy. Which of the following clinical findings is most likely to be characteristic of this group of patients? (A) Cachexia (B) Cardiac murmur (C) Icterus (D) Loss of sensation (E) Splenomegaly
A. Cachexia
Echinocandins inhibit which of the following fungal-specific cell features? (A) Cell wall glucans (B) Cell wall chitin (C) Cell membrane ergosterol (D) Cell membrane cholesterol (E) DNA synthesis
A. Cell wall glucans
Which of the following is not a mechanism of T cell tolerance? (A) Inhibition of T cell activation by interleukin-12 from regulatory T cells (B) Apoptosis induced by Fas ligand binding to Fas (C) Anergy induced by B7-1 or B7-2 binding to CTLA-4 (D) Anergy induced by peptide-major histocompatibility complex (MHC) binding to T cell receptors (TCRs) without B7-1 or B7-2 binding to CD28 (E) TCR-mediated up-regulation of Bim or similar pro-apoptotic proteins
A. Inhibition of T cell activation by IL-12 from regulatory T cells.
Hyperacute graft rejection is caused by (A) Preformed antibodies (B) CD4 lymphocytes (C) CD8 lymphocytes (D) Platelets (E) Circulating immune complexes
A. Preformed antibodies
Most effective vaccines that are currently in widespread use are specific for pathogenic viruses, and the immunity induced by the vaccines is mediated largely by antibodies. Which of the following statements accurately describes the major mechanism by which these vaccine-dependent antibody responses protect immunized persons from infection? (A) The antibodies bind extracellular viral particles and prevent them from infecting cells. (B) The antibodies bind to viral antigens on the surface of infected cells and promote phagocytosis of the cells. (C) The antibodies bind to viral antigens on the surface of infected cells and promote complement-mediated lysis of the cells. (D) The antibodies bind to extracellular viral particles and target Fc receptor-expressing cytolytic T lymphocytes to kill the viruses. (E) The antibodies bind to viral envelope proteins and induce signals that inhibit viral replication.
A. The antibodies bind extracellular viral particles and prevent them from infecting cells
Which of the following mechanisms contributes to the change from B cell production of membrane Ig to secreted Ig? (A) V(D)J recombinase-mediated deletion of the exon encoding the transmembrane domain (B) Alternative processing of primary RNA transcripts to remove the transmembrane domain and include a secretory tail piece (C) Increased vesicular exocytosis of intracellular stores of the secretory form of Ig (D) Switch recombinase-mediated recombination of the heavy chain locus to juxtapose the V(D)J segment with the exon encoding a secretory tail piece (E) Up-regulation of ectoenzymes that proteolytically cleave membrane Ig heavy chains just proximal to the membrane
B. Alternative processing of primary RNA transcripts to remove the transmembrane domain and include a secretory tail piece.
Individuals with the class I HLA-B27 allele have a 90-fold greater chance of developing which of the following inflammatory diseases, relative to HLA-B27-negative individuals? (A) Rheumatoid arthritis (B) Ankylosing spondylitis (C) Pemphigus vulgaris (D) Diabetes mellitus type 1 (insulin-dependent) (E) Multiple sclerosis
B. Anklosing spondylitis
Which of the following conditions is not associated with immune complex deposition? (A) Arthus reaction (B) Autoimmune hemolytic anemia (C) Serum sickness (D) Systemic lupus erythematosus (E) Poststreptococcal glomerulonephritis
B. Autoimmune hemolytic anemia
Which of the following thermally dimorphic fungi grow in the human host as yeast-like cells with broad-based buds? (A) Histoplasma capsulatum (B) Blastomyces dermatitidis (C) Coccidioides immitis (D) Sporothrix schenckii (E) Paracoccidioides brasiliensis
B. Blastomyces dermatitidis
An epidemiologic study of cancer deaths recorded in the last half of the 20th century is conducted. The number of deaths for one particular type of cancer has been increasing in developed nations. Which of the following neoplasms was most likely to be identified by this study? (A) Angiosarcoma of the liver (B) Carcinoma of the lung (C) Colorectal carcinoma (D) Gastric adenocarcinoma (E) Leukemia
B. Carcinoma of the lung
Which of the following NNRTIs is commonly used as a first-line agent to treat HIV infection and has vivid dreams and dizziness as common potential side effects? A. Nevirapine B. Efavirenz C. Rilpivirine D. Etravirine
B. Efavirenz
Organ rejection by the donor is a major impediment to life-saving organ transplantation. Understanding the causes and time course or organ rejection is important so that appropriate treatment and prevention strategies can be developed. Which feature of acute rejection is not shared by hyper acute rejection? A. Deposition of C4d in peritubular capillaries B. Effector T cells C. Initiation of clotting cascade D. Initiation of complement cascade E. Neutrophil infiltrates
B. Effector T cells
Which of the following is not an effector mechanism of antibody-mediated disease? (A) Opsonization and phagocytosis of cells (B) Fas-dependent apoptosis of cells (C) Complement- and Fc receptor-mediated inflammation and tissue injury (D) Antibody stimulation of cell surface receptors in the absence of the physiologic ligands (E) FceR crosslinking
B. Fas-dependent apoptosis of cells
Which of the following should receive the life attenuated influenza vaccine preferentially? A. Adults >65 yrs old B. Healthy children age 2 - 8 C. Immunsuppressed patients D. Pregnant patients
B. Healthy children age 2 - 8
When evaluating patients w/ bleeding disorders, the most important information is gained from the: A. Clotting time B. History C. Platelet count D. Partial thromboplastin time E. Prothrombin tim
B. History
Which of the following is a common cause of a febrile rash illness and seizures in infants? A. Human parvovirus B. Human herpes virus - 6 C. Rubella D. Human herpes virus - 8 E. CMV
B. Human herpes virus - 6
A 14 year old boy is brought to the pediatrician's office in midsummer because of an itchy, blistering rash on his calves and forearms. The rash developed 24 hr after he returned from a weekend Boy Scout camping trip. The pediatrician suspects the lesion is caused by poison ivy. If the doctor is correct, which one of the following is not a prominent component in the immunologic mechanisms causing the skin lesions? (A) T cells (B) IgE-coated mast cells (C) Interferon-γ (D) Endothelial adhesion molecules (E) Chemokines
B. IgE-coated mast cells
Which of the following is a characteristic of the influenza virus? A. Influenza is part of the paramyxovirus family B. Influenza has a segmented genome C. Influenza is a DNA virus D. Influenza only causes disease in humans
B. Influenza has a segmented genome
Which of the following anatomic regions is normally protected from pathogens only by humoral immune responses and not by cell-mediated immune responses? (A) Skin (B) Intestinal lumen (C) Intestinal epithelium (D) Central nervous system (E) Spleen
B. Intestinal lumen
A young adult is exposed to a virus that infects and replicates in mucosal epithelial cells of the upper respiratory tract. One component of the protective immune response to this viral infection is mediated by CD8+ cytolytic T lymphocytes (CTLs), which recognize and kill virus-infected cells. The CTLs can recognize and kill the infected cells because (A) In response to interferon-γ secreted during the innate immune response to the virus, the mucosal epithelial cells express class II MHC, with bound viral peptides, on their cell surfaces. (B) Mucosal epithelial cells, like all nucleated cells, express class I MHC molecules and are able to process cytoplasmic viral proteins and display complexes of class I MHC and bound viral peptides on their cell surfaces. (C) Antibodies specific for viral antigens bind to these antigens on infected cell surfaces and engage Ig Fc receptors on the CTL, thereby targeting the CTL to the infected cells. (D) Virus-infected mucosal epithelial cells migrate to draining lymphoid tissues, where they present viral peptide antigens to naive CD8+ T cells. (E) Viral infection of the mucosal epithelial cells stimulates them to express E-selectin, which promotes CD8+ T cell adhesion.
B. Mucosal epithelial cells, like all nucleated cells, express class I MHC molecules and are able to process cytoplasmic viral proteins and display complexes of class I MHC and bound viral peptides on their cell surfaces
The health department has notified you that a young child has a skin lesion on her face. Because the family raises goats, it is suspected that the lesion may be due to orf virus, a poxvirus seen in livestock that can be transmitted to humans. What rapid microscopic examination could you perform to detect poxvirus? A. Thin section of urine B. Negative stain of blister fluid C. SEM of skin to show the lesion surface D. X-ray microprobe analysis to determine the elemental composition
B. Negative stain of blister fluid
Which of the following is the most common known primary immunodeficiency with a prevalence of 1 in 700 white individuals? (A) X-linked agammaglobulinemia (B) Selective IgA deficiency (C) Common variable immunodeficiency (D) Chronic granulomatous disease (E) Chédiak-Higashi syndrome
B. Selective IgA deficiency
Which of the following tests is frequently used to help make the diagnosis of infections due to Aspergillus fumigatus? (A) Test for polysaccharide capsule in serum (B) Test for galactomannan in serum (C) Demonstration of yeast-like cells by histopathology (D) Fungal culture growing an isolate with aseptate hyphae (E) Analysis of cerebrospinal fluid demonstrating encapsulated yeast cells
B. Test for galactomannan in serum
A 60 year old woman is in hospital for an elective hernia repair. On physical examination she is afebrile and normotensive. A serum glucose value of 120 mg/dL is obtained. Later on that day, another glucose test is ordered unnecessarily, and the value is noted to be 124 mg/dL. Which of the following statements best explains these findings? (A) A lack of sensitivity for this test is indicated by the difference in values. (B) The coefficient of variation for this test explains the difference in results. (C) There is an inaccuracy in one of the test results. (D) You have fortuitously discovered that she has diabetes mellitus. (E) 20 ml of blood removed via phlebotomy for the tests accounts for the difference.
B. The coefficient of variation for this test explains the difference in results
A 7 month old boy is evaluated in the clinic for recurrent bacterial infections. His tonsils are not visible on physical examination. Serum immunoglobulin A (IgA) and IgG levels are markedly decreased, and serum IgM levels are slightly below normal. Careful examination of this infant reveals white plaques along the buccal mucosa, palate, and tongue, consistent with oral candidiasis (thrush). Analysis of blood cells reveals normal numbers of B cells and very few CD3+ cells. In addition, maternally-derived T cells, as determined by HLA typing, are detectable. The infant's mother reports that two of her three brothers died of infection as young children. Collectively, this presentation and history are most consistent with which of the following disorders? (A) X-linked agammaglobulinemia (B) X-linked severe combined immunodeficiency disease (X-linked SCID) (C) Common variable immunodeficiency (D) X-linked hyper-IgM syndrome (E) Adenosine deaminase deficiency (ADA)
B. X-linked SCID
If X represents application of an initiator (polycyclic hydrocarbon) and Y the application of a promoter (croton oil), which of the following exposures will result in carcinogenesis? (A) X (B) XYYYYYYYYYYYYYYYYY (C) X Y Y (D) YYYYYYYYYYYYYYYYYX (E) YYYYYYYYYYYYYYYYYY
B. XYYYYYYYYYYYY
A common strategy by which microbes survive their host's immune responses involves changing the structures of the molecules they produce so that they are no longer recognized by the host's immune system. This strategy, called antigenic variation, is most likely to allow evasion of which type of immune recognition? (A) Toll-like receptor-dependent recognition of microbes by cells of the innate immune system (B) Mannose receptor-dependent recognition of microbes by cells of the innate immune system (C) Antibody recognition of microbial cell surface molecules (D) Natural killer cell inhibitory receptor recognition of class I major histocompatibility complex (MHC) molecules on infected cells (E) T cell receptor recognition of microbial cell wall lipid antigens
C. Antibody recognition of microbial cell surface molecules
Which of the following is an example of how the innate immune response stimulates or modifies adaptive immunity? (A) Tumor necrosis factor (TNF) secreted by helper T cells enhances adhesion molecules on endothelial cells and promotes recruitment of inflammatory cells. (B) Interferon (IFN)-γ produced by T helper cells is a potent activator of macrophages, allowing killing of phagocytosed microbes. (C) B7-1 expression on antigen-presenting cells is up-regulated in response to signaling through Toll-like receptors, thus enabling costimulation of T cells. (D) Infected cells coated by IgG3 are recognized by Fc receptors on natural killer cells, allowing efficient killing of the infected cells. (E) Double-stranded RNA of replicating viruses potently stimulates Type I IFN expression by fibroblasts, inducing an "antiviral state" in neighboring, uninfected cells.
C. B7-1 expression on antigen-presenting cells is up-regulated in response to signaling through Toll-like receptors, thus enabling costimulation of T cells
Both CD28 and CTLA-4 are receptors on T cells that are critical for regulating T cell activation. In which one of the following ways does CD28 differ from CTLA-4? (A) Only CD28 binds the costimulatory ligands B7-1 and B7-2 expressed on professional antigen-presenting cells. (B) CD28 counteracts positive, pro-proliferative T cell signals delivered by CTLA-4. (C) CD28 is constitutively expressed on naive T cells, whereas CTLA-4 is expressed on activated T cells. (D) CD28 binds its ligand with 10-fold greater affinity than does CTLA-4. (E) CD28 is important for delivering "signal 1" for T cell activation, whereas CTLA-4 is important for delivering "signal 2."
C. CD28 is constitutively expressed on naive T cells, whereas CTLA-4 is expressed on activated T cells.
Which of the following mechanisms does not contribute to the generation of a cytolytic T lymphocyte (CTL) response to a viral infection? (A) Dendritic cells phagocytose infected cells or viral particles and present them to naive CD8+ T cells via the class I MHC pathway. (B) Dendritic cells are infected with the virus and present viral peptides to naive CD8+ T cells via the class I MHC pathway. (C) CTLs are directly activated by CD40L expressed on activated helper T cells through CD40. (D) Helper T cells secrete cytokines, such as interleukin-2, that promote the proliferation and differentiation of CD8+ T cells. (E) Helper T cells activate infected antigen-presenting cells (APCs) via the CD40 ligand-CD40 pathway, and the activated APCs present viral peptides to naive CD8+ T cells via the class I MHC pathway.
C. CTLs are directly activated by CD40L expressed on activated helper T cells through CD40
A 35 year old man with a family history of colon carcinoma undergoes a surveillance colonoscopy. It reveals hundreds of polyps in the colon and two focal 0.5 cm ulcerated areas. A biopsy from an ulcer is shown below and reveals irregularly shaped glands that have penetrated into the muscular layer. Which of the following molecular events is believed to occur very early in the evolution of his colonic disease process? (A) Activated tumor suppressor genes (B) Amplified HER2/neu (C) Heterozygous p53 gene (D) Inherited APC germline mutation (E) Translocation of BCL2 from mitochondria to cytoplasm
C. Heterozygous p53 gene
Approximately 30-60 minutes after being bitten by a 'bug,' a 16 yr old man noticed a localized swelling and erythema in the affected area. These changes are caused by which of the following physiologic responses? A. Altered plasma oncotic pressure B. Increased arterial hydrostatic pressure C. Increased vascular permeability D. Lymphatic obstruction E. Venous obstruction
C. Increased vascular permeability
A 59 yr old man has experienced chest pain at rest for over 1 year. He develops crushing chest pain, collapses, and dies to to arrhythmia. The figure below shows a cross section of his left anterior descending artery. Which of the following laboratory findings has a casual relationship to this lesion? A. Absent C-reactive protein B. Inherited deficiency in VEGF C. Low HDL cholesterol D. Low total serum cholesterol E. Positive VDRL
C. Low HDL cholesterol
An epidemiologic study investigates the potential cellular/molecular alterations that may contribute to the development of cancers in a population. Molecular data from resected colonic lesions show changes involved in the evolution of a sporadic colonic adenoma into an invasive carcinoma. Which of the following best describes the mechanism producing these changes? (A) Extensive regeneration of tissues increases the risk of cancer-causing mutations. (B) Inherited defects in DNA repair genes increase the susceptibility to develop cancer. (C) Malignant transformation involves accumulation of mutations in protooncogenes and tumor suppressor genes in a step-wise fashion. (D) Overexpression of growth factor receptor genes are associated with poor prognosis. (E) Protooncogenes can be activated by chromosomal translocation.
C. Malignant transformation inovles accumulation of mutations in protooncogenes and tumor suppressor genes in a step-wise fashion.
Which of the following statements about immune complex-mediated diseases is false? (A) Immune complexes may contain antibodies bound to either self or foreign antigens. (B) Immune complex-mediated diseases generally show systemic manifestations. (C) Pathologic features of immune complex diseases are determined by the cellular source of the antigen. (D) Small complexes are deposited in vessels more than large complexes, which are usually efficiently phagocytosed. (E) Complexes containing cationic antigens are more likely to produce severe, long-lasting injury by depositing in blood vessels and renal glomeruli.
C. Pathologic features of immune complex diseases are determined by the cellular source of the Ag
A 20 yr old man incurs blunt trauma to his upper outer arm. On physical examination, there is a 2x3 cm contusion. The initial soft tissue bleeding stops in a few minutes, the size of the bruise does not increase and the soft tissue bleeding resolves. Which of the following chemical mediators is most important in this episode of hemostasis? A. Factor VIII B. Leukotriene C. Plasminogen D. Prostacyclin E. Prostaglandin
C. Plasminogen
While shaving one morning, a 23 yr old man nicks his lip w/ a razor. Seconds after the injury, the bleeding stops. Which of the following mechanisms is most likely to reduce blood loss from a small dermal vein? A. Fibrin polymerization B. Neutrophil chemotaxis C. Platelet aggregation D. Protein C activation E. Vasodilation
C. Platelet activation
A cut-off value must be chosen to separate normal from abnormal. Selecting this value virtually always involves balancing sensitivity and specificity, although the actual value may be arbitrary.A test with high sensitivity will not miss many patients who have the disease. The sensitivity of a clinical laboratory test is defined as the number of true positive test results divided by the sum of true positive and false negative test results. Which of the following statements about the sensitivity of a clinical laboratory test is true? (A) A very sensitive test is always a false positive. (B) Sensitivity is the probability that an individual who does not have the disease will test positive. (C) Sensitivity is the probability that an individual with the disease will test positive. (D) Sensitivity is the same as precision.
C. Sensitivity is the probability that an individual with the disease will test positive
In the setting of candidemia, which of the following statements is(are) true about intravenous catheters? (A) Intravenous catheters are frequent sources of the entry of Candida species into the bloodstream. (B) Fungal biofilms that form on intravenous catheters often make it very difficult to cure catheter-related candidemia without device removal. (C) Systemic candidiasis always requires intravenous therapy for treatment. Therefore infected catheters should remain in place until completion of therapy. (D) A and B, not C (E) A, B, and C
D. A and B, not C
Which of the following statements is(are) true about vulvovaginal candidiasis? (A) Single dose fluconazole therapy is an acceptable treatment for routine cases of this condition. (B) Vulvovaginal candidiasis is most commonly associated with alterations of the vaginal microbiota or hormone fluxes. (C) Topical antifungal therapy is rarely effective for this condition (D) A and B, not C (E) A, B, and C
D. A and B, not C
MHC class 2 molecules are expressed on: (A) All cells (B) All epithelial cells (C) All lymphocytes (D) All antigen presenting cells (E) Exclusively dendritic cells
D. All antigen presenting cells
A graft between members of the same species is termed an (A) Autograft (B) Isograft (C) Xenograft (D) Allograft (E) Prograf
D. Allograft
The role of HA in the pathogenesis of influenza is to: A. Degrade protective mucus B. Release progeny virus C. Transcribe viral RNA D. Bind cell surface sialic acid
D. Bind cell surface sialic acid
Neutralizing antibodies... A. Facilitate macrophage entry of viruses like dengue, thus increasing disease B. Are the primary means to clear enveloped viruses C. Must be present before a person gets infected to have an effect D. Bind to viral surfaces and block subsequent infection of cells
D. Bind to viral surfaces and block subsequent infection of cells
Naive CD8+ T cells require signals in addition to T cell receptor recognition of peptide-MHC to become activated and differentiate into cytolytic T cells. These signals are called costimulatory signals and are provided by professional antigen-presenting cells (APCs), such as dendritic cells. If a virus infects epithelial cells in the respiratory tract but does not infect professional APCs, what process ensures that naive T cells specific for viral antigens will become activated? (A) Cross-reactivity, whereby the naive CD8+ T cell recognizes a self antigen that is structurally similar to a viral antigen presented by dendritic cells (B) Crossover, whereby part of the viral genome is exchanged with part of one chromosome of the host (C) Crosstalk, whereby signals generated by the virus binding to class I MHC molecules intersect with T cell receptor signaling pathways (D) Cross-presentation, whereby infected epithelial cells are captured by dendritic cells, and the viral proteins originally synthesized in the epithelial cells are processed and presented in association with class I MHC molecules on the dendritic cell (E) Cross-dressing, whereby viral infection of the epithelial cell stimulates the expression of surface molecules that are typically found only on dendritic cells
D. Cross-presentation, whereby infected epithelial cells are captured by dendritic cells, and the viral proteins originally synthesized in the epithelial cells are processed and presented in association with class I MHC molecules on the dendritic cell
A child who suffers from a persistent viral infection is found to have a deficiency in lymphocyte production and very few T and B cells. Other bone marrow-derived cells are produced in normal numbers, and MHC molecule expression on cells appears normal. Transfusion of mature T cells from an unrelated donor who had recovered from a previous infection by the same virus would not be expected to help the child clear his infection. Which one of the following is a reasonable explanation for why this therapeutic approach would fail? (A) Viral infections are cleared by antibodies, not T cells. (B) The patient's own immune system would destroy the transfused T cells before they could respond to the viral infection. (C) T cells recognize peptides, not viral particles. (D) Donor T cell viral antigen recognition is restricted by MHC molecules not expressed in the patient. (E) In responding to the previous infection, the donor would have used up all his T cells specific for that virus.
D. Donor T cell viral antigen recognition is restricted by MHC molecules not expressed in the patient
All of the following are key mediators of immediate hypersensitivity reactions except (A) Mast cells (B) Basophils (C) IgE (D) Macrophages (E) TH2 cells
D. Macrophages
If a virus causes down regulation of MCH antigens on a host cell, which of the following immune cells recognizes the loss of MHC and kills the infected cell? A. Eosinophil B. B cell C. CD8+ T cell D. NK cell
D. NK cell
A 3 year old boy, who is small for his age, has a history of pyogenic (pus-producing) infections and cutaneous skin abscesses. Physical examination is remarkable for high fever, enlarged liver and spleen, and swollen cervical lymph nodes. A culture from an abscess on his arm reveals Staphylococcus aureus, a Gram-positive bacterium that is also catalase-positive. Immunoglobulin and complement levels are normal. Results of the nitroblue tetrazolium test are consistent with a diagnosis of chronic granulomatous disease (CGD). The boy's immunodeficiency involves impaired generation of which of the following? (A) C5a (B) C-reactive protein (C) Mannose-binding lectin (D) Reactive oxygen intermediates (E) Membrane attack complex
D. Reactive oxygen intermediates
An elderly obese patient with diabetes mellitus has been hospitalized for nearly two weeks to achieve optimal control of her diabetes and to manage her congestive heart failure. She has undergone frequent venipunctures for laboratory tests as well as intravenous fluid therapy. After a very difficult venipuncture with prolonged application of the tourniquet, the serum K+ was found to be 6.8 mmol/L. Which of the following is the appropriate course of action? (A) Do nothing, this is an expected result. (B) Interpret the data based on the serum Na+ level. (C) Order the lab to repeat the test using the same specimen. (D) Request that the lab obtain a new specimen and repeat the test. (E) Start dialysis immediately.
D. Request that the lab obtain a new specimen and repeat the test
Which of the following statements about T cell tolerance to self proteins is true? (A) Self proteins are not presented by the class I pathway because only microbial proteins, and not self proteins, are ubiquinated in the cytosol. (B) Peptides derived from self proteins are not presented by the class I or class II pathways because MHC molecules are expressed only in response to infections. (C) Self proteins are not presented by the class II pathway because endosomal acidic proteases digest microbial proteins but not eukaryotic proteins. (D) Self peptide/self MHC complexes are formed and displayed by antigen-presenting cells in both class I and class II MHC pathways, but T cells that recognize these complexes usually are not present or are functionally inactive. (E) Peptides derived from self proteins are not displayed by MHC molecules because they usually are displaced by the more abundant microbial peptides.
D. Self peptide/self MHC complexes are formed and displayed by APCs in both class I and class II MHC pathways, but T cells that recognize these complexes usually are not present or are functionally inactive.
A 23 year old woman has had worsening malaise along with a malar skin rash persisting for 3 weeks. On physical examination, she has an audible friction rub on auscultation of the chest, along with a faint systolic murmur. An echocardiogram reveals small vegetations on the mitral valve and adjacent ventricular endocardium. Laboratory studies show a positive antinuclear antibody test, with a titer of 1:2048. Which of the following is the most likely diagnosis? (A) Adenocarcinoma of the pancreas (B) Complicated acne (C) Polyarteritis nodosa (D) Systemic lupus erythematosus (E) Wegener's granulomatosis
D. Systemic lupus erythematosus
Which of the following statements regarding antigenic shift is true? A. It is caused by minor mutations in HA and NA B. It causes local and national epidemics only C. It occurs only in Influenza B and C D. The recominbation events leading to changes in HA and NA often occur in birds
D. The recombination events leading to changes in HA and NA often occur in birds
A 7 month old boy is evaluated in the clinic for recurrent bacterial infections. His tonsils are not visible on physical examination. Serum immunoglobulin A (IgA) and IgG levels are markedly decreased, and serum IgM levels are slightly below normal. This infant should not be given the measles(A) The vaccine would have no effect because he is not susceptible to infection with measles, mumps, or rubella. (B) The vaccine would have no effect because he cannot mount an appropriate humoral response. (C) The vaccine could be dangerous because he is predisposed to develop a type I hypersensitivity response to the MMR vaccine. (D) The vaccine could be dangerous because vaccination with MMR would put him at risk for developing a fatal infection. (E) Vaccination with MMR is not contraindicated in his case and should be performed to prevent future infection.mumps-rubella (MMR) vaccination because
D. The vaccine could be dangerous because vaccination w/ MMR would put him at risk for developing a fatal infection.
A 5 year old boy has a history of recurrent pneumococcal pneumonia, Pneumocystis carinii pneumonia (PCP), and bacterial ear infections. His maternal uncle and an older brother experienced the same symptoms, but he has an older sister who is healthy. Laboratory studies indicate normal numbers of B cells and T cells, and the serum contains mostly IgM and very little IgG. Which of the following abnormalities would be unlikely in this patient? (A) The IgG antibodies that are present are of lower affinity for antigen than of those of a healthy individual. (B) Lymph nodes are without well-developed follicles containing germinal centers. (C) Macrophage killing of intracellular microbes is impaired. (D) There is limited diversity in the repertoire of IgM antibodies produced. (E) There is no evidence of somatic mutation of IgM variable regions.
D. There is limited diversity in the repertoire of IgM Abs produced.
Which of the following best describes the classic presentation of shingles? A. Diffuse macular rash and pharyngeal erythema B. Vesiculo-pustular rash involving the palms and soles of the feet C. Vesicular rash that is primarily not the truck and abdomen D. Vesicular rash in a dermatomal distribution E. Bullous rash localized to one area of the body
D. Vesicular rash in a dermatomal distribution
Some proliferative conditions and cancers may have a genetic basis. Which of the following conditions is inherited in an autosomal recessive fashion? (A) Hereditary nonpolyposis colon cancer (B) Li-Fraumeni syndrome (C) Retinoblastoma (D) Xeroderma pigmentosum (E) None of these conditions is inherited.
D. Xeroderma pigmentosum
A 26 year old African-American woman visits her physician because of a prominent rash over her nose and cheeks, which she first noticed following her return from a vacation in Jamaica. She also complains of fever, fatigue, weight loss, and joint pain during the last several months. Serologic tests are conclusive for systemic lupus erythematosus (SLE), an autoimmune disease that can manifest clinically with rashes, arthritis, glomerulonephritis, hemolytic anemia, thrombocytopenia (low platelet count), and central nervous system involvement. The principal diagnostic test result specific for this condition is a high titer of autoantibodies against which of the following? (A) Glomerular basement membrane (B) Rh blood group antigen (C) Myelin (D) Double-stranded DNA (E) IgG
D. dsDNA
A study was conducted to determine the predictive value of a commonly used test for myocardial infarction, creatine kinase isoenzyme MB (CK-MB). 600 patients with chest pain in the coronary intensive care unit were tested for elevated creatine kinase MB fraction. The following results were obtained: CK-MB Patients With MI Patients Without MI Test Elevated 450 5 Test Not Elevated 50 95 The positive predictive value of an elevated CK-MB is (A) 66% (B) 83% (C) 90% (D) 95% (E) 99%
E. 99%
A 25 year old man who received a renal transplant 6 months ago is found to have elevated serum creatinine and urea nitrogen levels on a routine post-transplant checkup, suggesting dysfunction of the allograft. Possible causes you should consider include which of the following? (A) Acute cellular allograft rejection (B) Infection with polyomavirus (C) Infection with cytomegalovirus (D) Toxicity of an immunosuppressive drug (E) A, B, C, and D
E. A, B, C, and D
A 56 year old man with a 120 pack-year smoking history is referred to you for consideration of surgical resection after he is found to have a new 2 cm lung mass on a chest X-ray. After you have reviewed his records, you want to be able to tell him whether surgery will cure his disease. Factors that would influence whether a surgical resection would be curative include (A) Cell type of the neoplasm (B) Location of the neoplasm (C) Stage of the neoplasm (D) Whether the neoplasm is benign or malignant (E) A, B, C, and D
E. A, B, C, and D
Candida albicans biofilms are characterized by which of the following characteristics? (A) A mixture of yeast-like and hyphal fungal forms (B) Extracellular matrix (C) Attachment to a surface, either biological or artificial (D) Exotoxin production (E) A, B, and C, not D (F) A, B, C, and D
E. A, B, and C, not D
Which of the following terms best describes the mechanism by which effector T cells are deleted by repeated stimulation by persistent antigen? (A) Passive cell death (B) Central tolerance (C) Peripheral tolerance (D) Death by neglect (E) Activation-induced cell death
E. Activation-induced cell death
Many vaccines now in development will include highly purified, recombinant, or synthetic peptide antigens. These vaccine antigens are expected to stimulate highly specific immune responses, but they are less immunogenic than vaccines containing intact killed or live microbes. Adjuvants are substances added to such vaccines to enhance their ability to elicit T cell immune responses. Which of the following statements about adjuvants is false? (A) Adjuvants induce local inflammation, thereby increasing the number of antigen-presenting cells (APCs) at the site of immunization. (B) Adjuvants stimulate the expression of costimulators on local APCs. (C) Adjuvants enhance local production of cytokines that promote T cell activation. (D) Adjuvants prolong the expression of peptide-MHC complexes on the surface of APCs. (E) Adjuvants bind to T cell antigen receptors and promote their proliferation.
E. Adjuvants bind to T cell antigen receptors and promote their proliferation
All of the following protein-protein interactions are involved in activation of naive helper T cells by antigen-presenting cells (APCs) except (A) Binding of peptide-MHC complexes on the APC to the TCR on the T cell (B) Binding of CD4 on the T cell to nonpolymorphic regions of class II MHC molecules on the APC (C) Binding of integrins on the T cell with adhesion ligands on the APC (D) Binding of B7-2 on the APC with CD28 on the T cell (E) Binding of CD40L on the T cell with CD40 on the APC
E. Binding of CD40L on the T cell w/ CD40 on the APC
Which of the following is typically not associated with T cell immunodeficiencies? (A) Cancer (B) Viral infection (C) Autoimmunity (D) Infection with intracellular microbes (E) Infection with pyogenic bacteria
E. Infection w/ pyogenic bacteria
A 12 yr old boy died of complications of ALL. An autopsy was performed and his aorta is show below. Histologic examination of the area marked but the arrow is most likely to show which of the following features? A. A core of lipid debris covered by a cap of smooth muscle cells B. A lipid core, granulation tissue, and hemorrhage C. Cholesterol clefts surrounded by smooth muscle cells and macrophages D. Foam cells (macrophages), areas of necrosis, and calcification E. Lipid-filled myointimal cells
E. Lipid filled myointimal cells
An 8 year old boy from the intermountain region of the United States is brought to the pediatrician with fever, rash, and pain in his knees and ankles. Pericarditis is evident on auscultation, and echocardiography confirms mitral valve regurgitation. Three weeks before this episode, the patient had experienced a sore throat but had not received medical attention. High titers of antistreptococcal antibodies are present in the serum. This child's disease is a result of which one of the following phenomena? (A) Clonal anergy (B) Peripheral tolerance (C) Epitope spreading (D) Central tolerance (E) Molecular mimickry
E. Molecular mimickry
A 41 year old man receives a renal transplant because of end-stage renal disease resulting from acute glomerulonephritis as a juvenile. Just after the graft is anastomosed, the kidney becomes cyanotic, mottled, and flaccid. A few drops of bloody urine are excreted. A renal biopsy is taken, and there is neutrophil accumulation within the arterioles, glomeruli, and peritubular capillaries. Which of the following is/are responsible for this condition? (A) CD4+ and CD8+ lymphocytes (B) IgE and histamine (C) Lymphokines (D) Natural killer cells (E) Preformed anti-donor antibodies
E. Preformed anti-donor antibodies
Which one of the following statements about primary and secondary antibody responses is false? (A) Antibodies in primary responses generally have lower affinity for antigen than those produced in secondary responses. (B) Secondary responses reach peak levels more quickly than primary responses. (C) Primary responses require higher concentrations of antigen for initiation than secondary responses. (D) Primary responses occur to all types of antigens, but secondary responses mostly occur only to protein antigens. (E) Primary responses are characterized by IgG antibodies, whereas secondary responses are dominated by IgM antibodies.
E. Primary responses are characterized by IgG Abs, whereas secondary responses are dominated by IgM Abs.
An 80 yr old woman falls down the steps leading to the entrance of the house of a relative who is hosting a family reunion. She is hospitalized for surgery to replace a broken hip. She is then moved to a nursing home, but she is unable to ambulate until about a month later. She gets up to bathe w/ assistance and she experiences the sudden onset of severe dyspnea (shortness of breath) and goes into cardiac arrest, from which she cannot be resuscitated. Which of the following is most likely to be the immediate cause of death found at autopsy? A. Acute bronchopneumonia B. Acute renal failure C. Complications of alcohol abuse D. Congestive heart failure E. Pulmonary embolism
E. Pulmonary embolism
A 5 year old child loses vision in the right eye. MR imaging shows a mass in the posterior chamber that nearly fills the globe. The child undergoes enucleation of the right eye. Molecular analysis of the neoplastic cells indicates absence of both copies of a tumor suppressor gene that controls the transition from the G to the S phase of the cell cycle. Which of the following genes is most likely to have the mechanism of action that produced this neoplasm? (A) BCL2 (B) hMSH2 (C) K-RAS (D) NF1 (E) RB
E. RB
Which of the following diagnostic tests for influenza allow for simultaneous detection of other respiratory viruses? A. Rapid Ag detection B. Viral culture C. DFA test and PCR D. Viral culture and PCR E. Rapid Ag detection and viral culture
E. Rapid Ag detection and viral culture
The mechanisms by which TH1 cells protect against microbes include all of the following except (A) Secretion of interferon (IFN)-γ, which activates microbicidal functions of macrophages (B) Expression of CD40 ligand, which binds to CD40 on macrophages and activates them (C) Secretion of IFN-γ, which promotes B cell production of opsonizing antibodies (D) Secretion of lymphotoxin and tumor necrosis factor, which enhance neutrophil killing of ingested microbes (E) Release of granzyme B, which stimulates apoptosis of bacteria
E. Release of granyzme B, which stimulates apoptosis of bacteria
The nucleoside reverse transcriptase inhibitors (NRTIs) are among the most commonly prescribed antiviral medications for HIV infection. Which of the following is NOT an NRTI? A. Zidovudine B. Lamivudine C. Abacavir D. Tenofovir E. Ritonavir
E. Ritonavir
A 61 yr old man had a MI one year ago, which was the first major illness of his life. He smokes a pack of cigarettes a day and has done so for the past 40 years. His father died of an MI at age 55. His cholesterol is elevated. He is employed as a urologic surgeon in private practice. Which of the following strategies would be most effective in this patient's management? A. Aggressive reduction of serum cholesterol to 250 mg/dL B. Genetic manipulation C. Hire a junior partner for his urologic surgery practice D. Rest by increasing sedentary activity E. Stop smoking and start a regular exercise program
E. Stop smoking and start a regular exercise program
In patients with advanced HIV infection, various microorganisms can cause opportunistic infections, diseases only seen in the face of severely compromised immune system. Which of the following is NOT a common cause of OIs in AIDS? A. Cryptococcus neoformans B. Pneumocystis jiroveci C. Mycobacterium avium-intracellulare (MAC) D. CMV E. Streptococcus pyogenes
E. Streptococcus pyogenes
Which of the following comparisons between TH1 and TH2 cells is true? (A) TH1 cells produce interleukin (IL)-1 but not IL-2, and TH2 cells produce IL-2 but not IL-1. (B) TH1 cells are class I major histocompatibility complex (MHC) restricted, and TH2 cells are class II MHC restricted. (C) The chemokine receptors CXCR3 and CCR5 are more highly expressed on TH2 cells than on TH1 cells. (D) TH2 cells are more likely to bind to E-selectin and P-selectin on endothelial cells than are TH1 cells. (E) TH1 cells produce interferon (IFN)-γ but not IL-4, and TH2 cells produce IL-4 but not IFN-γ.
E. TH1 cells produce IFN-gamma but not IL-4, and TH2 cells produce IL-4 but not IFN-gamma
A 40 year old man has a history of intravenous drug use. Physical examination shows needle tracks in his left antecubital fossa. He has mild scleral icterus (yellow eyeballs). Serologic studies for hepatitis HBsAg and antibodies to hepatitis HCV are positive. He develops hepatocellular carcinoma 15 years later at age 55. Which of the following best explains why this patient developed hepatocellular carcinoma? (A) Integration of these viruses in the vicinity of protooncogenes (B) The ability of these viruses to capture protooncogenes from the host DNA (C) These viruses cause immunosuppression (D) Viral genes inactivate RB and p53 expression (E) Virus-induced injury to liver cells followed by extensive regeneration of liver cells
E. Virus-induced injury to liver cells followed by extensive regeneration of liver cells
A 45 year old woman has had increasing malaise for 3 weeks. Yesterday she had an episode of hemoptysis. On physical examination, her vital signs show T 37.5°C, P 80/min, RR 19/min, and BP 140/90 mm Hg. A chest radiograph reveals a reticulonodular pattern of infiltrates. Laboratory studies show her serum creatinine is 3.8 mg/dL with urea nitrogen of 40 mg/dL. Her serum antinuclear antibody test is negative, but her anti-neutrophil cytoplasmic autoantibody test is positive. A lung biopsy is performed and reveals necrotizing granulomas with vasculitis. Which of the following is the most likely diagnosis? (A) Giant cell arteritis (B) Kawasaki syndrome (C) Polyarteritis nodosa (D) Takayasu arteritis (E) Wegener's granulomatosis
E. Wegener's granulomatosis
A 25 yr old female medical student is found to be anemic on a routine physical. She reports heavy menstrual bleeding throughout her life. She has also experienced frequent epistaxis (nosebleeds) and a "funny rash" on her legs whenever she takes aspirin. Her APTT was also found to be middy prolonged. Which diagnosis is most likely? A. Factor VIII deficiency B. Glanzmann thrombasthenia C. Liver failure D. Thrombin deficiency E. vonWillebrand disease
E. vonWillebrand disease
In a brain biopsy you find viruses by transmission electron microscopy (TEM) of thin section. Which of the following characteristics would you look for to narrow the possibilities of the kind of virus present so that you can identify it? A. Size of the nucleocapsid or capsid B. Location of the virus in the cell C. Whether the virus is budding and, if so, from which membranes D. Whether the virus is positively or negatively stained by H & E E. All of the above F. A, B, and C, NOT D
F. A, B, and C, NOT D