IM EX1

11 Dendritic cells, macrophages, and what other cell types are considered "professional antigen present- ing cells," capable of antigen presentation to T helper cells? (A) B cells (B) Basophils (C) Eosinophils (D) Mast cells (E) Neutrophils

(A) B cells

A 24-year-old woman presents with airway obstruc- tion secondary to laryngeal swelling. Her history is significant for episodes of recurrent facial swell- ing that began sometime in childhood. The ing, which often involves without recognizable precipitating events and lasts for 2 to 3 days. Laboratory tests reveal a deficiency involving the complement system. Which compo- nent of the complement system is deficient in this (A) c1 inhibitor (B) C3 convertase (C) C5 convertase (D) Mannose-binding lectin (E) Membrane attack complex

(A) C1 inhibitor

14 The intracellular signal initiated by antigen binding to the T-cell receptor is generated by which set of mol- ecules expressed on the T cell membrane? (A) CD3 (B) CD4 (C) CD28 dis- (D) CD45 absence of (E) CD152 following

(A) CD3

19 If a person had a genetic defect affecting perforin pro- duction, which cells and immune function would be affected? (A) Cytotoxic T cells and natural killer cells/cell killing (B) Dendritic cells/antigen presentation (C) Eosinophils and basophils/granule production (D) Macrophages and neutrophils/phagocytosis (E) Mast cells/fusion of granules to cell membrane

(A) Cytotoxic T cells and natural killer cells/cell killing

Which one of the following represents the major role of negative selection in the thymus? (A) Elimination of self-reactive T cells (B) Expansion of nonself-reactive T cells (C) Maturation of professional antigen presenting cells such as dendritic cells (D) Expression of T-cell receptors on mature T cell (E) Differentiation of Thl and Th2 CD4 T cells

(A) Elimination of self-reactive T cells

Activation of the complement system, directly results in which one of the following outcomes? (A) Enhanced phagocytosis (B) Expression of Toll-like receptors on phagocyte cell surface (C) Enhancement of immune-mediated neutralization (D) Proliferation of T cells (E) Interaction of Fc receptors with antibodies bound to antigens on the pathogen cell surface

(A) Enhanced phagocytosis

immune Which cytokine is essential for T-cell proliferation and is also necessary for the production of CD25-positive resultant regulatory T cells? (A) IL-2 (B) IL-3 (C) IL-4 (D) IL-5 (E) IL-6

(A) IL-2

13 Activation of macrophages is best achieved by which cytokine? (A) Interferon gamma (IFN-y) (B) Granulocyte monocyte colony-stimulating factor (GM-CSF) (C) Interleukin-1 (D) Macrophage chemotactic protein (MCP) (E) Transforming growth factor beta (TGF-B)

(A) Interferon gamma (IFN-y)

21 Which one of the following cytokines plays the most important role in protection against intracellular growth (reactivation) of Mycobacterium tuberculosis? (A) Interferon-y (B) Interleukin-2 (C) Interleukin-5 (D) Interleukin-10 (E) Tumor necrosis factor

(A) Interferon-y

T cells stimulated by peptide-MHC complexes, dis- played on antigen presenting cells, in the absence of costimulation undergo which one of the following processes? (A) Activation (B) Anergy (C) Apoptosis (D) Differentiation (E) Proliferation

(B) Anergy

A 6-month-old male is hospitalized with dissemi- nated Mycobacterium avium complex. His history is significant for recurrent episodes of otitis media which responded poorly to antibiotics and episodes of severe thrush and diaper rash. Based on this his- tory, an immunologic workup was done and the child diagnosed with an immune deficiency disorder. Deficiencies of which aspect of the immune response could best account for the child's medical history? (A) B cells (B) B and T cells (C) Complement (D) Macrophages (E) Neutrophils

(B) B and T cells

Neutrophils are attracted to the sites of extracellular bacterial infections by which two important chemo- tactic substances? (A) Bacterial mannose and lipopolysaccharide (B) Complement C5a and interleukin-8 (CXCL-8) (C) Histamine and complement C3b (D) Interleukin-7 and interleukin-16 (E) Leukotriene B4 and granulocyte colony- stimulating factor (G-CSF)

(B) Complement C5a and interleukin-8 (CXCL-8)

A person developed an extracellular bacterial infec- tion, and IgM was made in response. What is the most important protective function of IgM in this infection? (A) Antibody-dependent cell cytotoxicity (B) Complement activation (C) Direct lysis of bacterial cells (D) Neutralization of bacterial toxins (E) Opsonization

(B) Complement activation

38 Persons with helminth infections mount immunologic responses that involve IgE and eosinophils. Which two cytokines are most important for these responses to occur? (A) IL-1 and tumor necrosis factor (TNF) (B) IL-4 and IL-5 (C) IL-10 and transforming growth factor beta (TGF-B) (D) IL-12 and interferon gamma (IFN-y) (E) IFN-a and IFN-B

(B) IL-4 and IL-5

1 A 67-year-old woman is hospitalized with a fever of unknown origin. An elevated C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) sug- gest an ongoing systemic inflammatory response. Which cytokine is especially important in inducing elevations in CRP and ESR? (A) Interleukin-4 (B) Interleukin-6 (C) Interleukin-10 (D) Interleukin-12 (E) Interleukin-18

(B) Interleukin-6 (C

16 Which one of the following cells is the major source of tumor necrosis factor alpha (TNF-a), interleukin-1, and interleukin-12? (A) B cells (B) Macrophages (C) Mast cells (D) Thl cells (E) Th2 cells

(B) Macrophages

Which one of the following leukocytes is considered a "granulocyte"? (A) Macrophage (B) Neutrophil (C) Dendritic cell (D) Natural killer cell (E) Natural killer T cll

(B) Neutrophil

A l-year-old female presented with symptoms of sys- temic autoimmunity (lupus, diabetes, and arthritis), and upon genetic analysis it was found that the patient had a mutation n the Foxp3 gene locus. Which one of the following is an explanation for the clinical symp- toms observed? (A) Patient cannot produce antigen presenting cells (B) Patient cannot generate regulatory CD4 CD25 T cells (C) Patient is unable to produce antibodies (D) Patient cannot produce anti-inflammatory cytokines (E) Patient NK cells have no inhibitory signal

(B) Patient cannot generate regulatory CD4 CD25 T cells

A 36-year-old woman with severe allergy to yellow jackets was stung multiple times at a soccer game. Within minutes she developed respiratory distress and became unconscious. Which mediator is prima- rily responsible for this reaction? (A) Complement (B) leG (C) Histamine (D) TNF (E) Norepinephrin

(C) Histamine

Plasma cells secreting IgA are especially abundant in which body site? (A) Bone marrow (B) Germinal centers of cervical lymph nodes (C) Lamina propria of mucosa (D) Thoracic duct (E) White pulp of the spleen

(C) Lamina propria of mucosa

Following an initial expansion of B cells in response to microbial peptides, a memory pool of B cells is generated and maintained in the individual in many cases throughout life. Recently, it was discovered that two memory cell types were generated in response to microbial challenge. Upon rechallenge with the microbe, the patient is protected from infection. Which one of the following explanations accounts for this observation? (A) Circulating memory B cells are actively producing antibodies in the absence of antigen (B) antibodies, antikedng Circulating i memory B cells will produce however, only upon encounter with the she microbial antigen (C) Long-lived plasma cells are actively producing antibodies in the absence of antigen (D) Long-lived plasma cells will produce antibodies, however, only upon encounter with the microbial antigen (E) TLR signaling to the circulating memory B cells will induce rapid production of antibodies in response to antigen encounter

(C) Long-lived plasma cells are actively producing antibodies in the absence of antigen

Which cells utilize reactive oxygen and nitrogen spe- cies and lysosomal enzymes to kill pathogens? (A) Cytotoxic T cells (B) Natural killer T (NKT) cells (C) Macrophages (D) Natural killer (NK) cells (E) Thl cells

(C) Macrophages

Antigen presenting cells (APCS) are required for T-cell recognition of specific antigen and activation. APCS accomplish this task by presenting antigen in the text of which of the following molecules? (A) T-cell receptor (TCR) (B) Toll- -like receptor (TLR) (C) Major histocompatibility complex (MHC) (D) Killer inhibitory receptor (KIR) (E) Fc receptor (FcR)

(C) Major histocompatibility complex (MHC)

A 4-year-old child has atopic dermatitis due to severe allergies to dust, animal dander, and many kinds of pollens. Mediators released from which cell type are responsible for the clinical manifestations immedi- ately following exposure to these substances? (A) B cells (B) Macrophages (C) Mast cells (D) Thl cells (E) Th2 cells

(C) Mast cells

3Vaccination operates to generate a humoral immune response to the immunogen(s). Which one of the fol- lowing represents the critical function of the resultant humoral response in protecting vaccinated patients from future infections by targeted pathogenic agents? (A) Opsonization (B) Extravasation (C) Neutralization (D) Complement activation (E) Antibody-dependent cell cytoxicity (ADCC) selection

(C) Neutralization

A person develops a viral infection and both T and B cells become activated to fight the infection. In which way is antigen recognition by B cells different from antigen recognition by T cells? (A) B cells home to the paracortex of lymph nodes where they recognize the antigens trapped by helper T cells (B) В B cells recognize the antigens that have been processed and presented by follicular dendritic cells (C) B cells undergo receptor editing to change receptors that fail to bind to an antigen (D) Be cells utilize membrane immunoglobulin molecules to bind to antigen in its natural state (E) The antigen receptors on a single B cell have a broad specificity, and are able to recognize several chemically unrelated antigens

(D) Be cells utilize membrane immunoglobulin molecules to bind to antigen in its natural state

34 What response of T cells plays a role in the patho- genesis of shock following the binding of TSST-1 and similar molecules? (A) Anergy (B) Apoptosis (C) Cell cytotoxicity (D) Cytokine secretion (E) Memory cell differentiation

(D) Cytokine secretion

Which one of the following represents a mechanism of tumor evasion from the immune response? (A) Deviation of helper T cells to type-l or Thl cells (B) Production of interferon-y (IFNY) by the tumor (C) Cross-presentation of tumor antigen by dendritic cells to activate CD8 T cells (D) Decreased expression of class I MHC on tumor cells (E) Tumor inhibition of angiogenesis

(D) Decreased expression of class I MHC on tumor cells

A 45-year-old female presents with anorexia and some abdominal pain. Fecal smears reveal the presence of Taenia eggs, products of a parasitic tapeworm infec- tion. Which one of the following cells would be effective in defence against this parasite? (A) Platelets (B) Erythrocytes (C) Neutrophils (D) Eosinophils (E) Monocytes

(D) Eosinophils

A 14-year-old girl presented with an itchy, erythema- tous rash following exposure to poison ivy. Which term describes the role of poison ivy oils in this response? (À) Allergen (B) Carrier (C) Cytokine (D) Hapten (E) Immunogen

(D) Hapten

A 43-year-old woman has a diagnosis of relapsing and remitting multiple sclerosis. Which cytokines pre- dominate in the CNS during periods of remission and what is their effect? (A) CC-chemokines/recruit Thl cells into CNS (B) y-Interferon and tumor necrosis factor-c (TNF-a)/support proliferation of oligodendrocytes (C) IL-2, IL-5, TNF-/activate microglia and astrocytes to secrete matrix metalloproteases (D) IL-4, IL-10, TGF-B/downregulate Thl cells (E) IL-17 and TNF-a/activate endothelial cells and memory T cells

(D) IL-4, IL-10, TGF-B/downregulate Thl cells

Antigens from which one of the following microbes would be presented on MHC class I molecules by macrophages? (A) Ascaris lumbricoides (B) Candida albicans (C) Haemophilus influenzae (D) Influenza virus (E) Streptococcus pneumoniae

(D) Influenza virus

Which cell type is primarily responsible for the inflam- mation seen in poison ivy rash? (A) B cells (B) Cytotoxic T cells (C) Eosinophils (D) Natural killer cells (E) Thl cells

(D) Natural killer cells

Which immune system cells recognize body cells with reduced expression of MHC class I molecules? (A) Cytotoxic T cells (B) Dendritic cells (C) Macrophages (D) Natural killer cells (E) Neutrophils

(D) Natural killer cells

Ablood sample from an individual with systemie lupus erythematosus was studied in a research project map- ping T-cell receptor specificities. Many T cells were discovered to express receptors specific for autolo- gous antigens. Failure of which process in the thymus leads to the large number of autoreactive patient's blood? (A) Affinity maturation (B) Antigen processing (C) Hematopoiesis (D) Negative selection (E) Receptor editing

(D) Negative selection

A 66-year-old man with advanced pancreatic cer develops cachexia. Which cytokine is responsible for the cachexia seen in certain debilitating infections? with cancer or KA) Interferon-a (A) (B) Interleukin-7 (C) Interleukin-17 (D) Transforming growth factor-B (E Jumor necrosis factor-a

(E Jumor necrosis factor-a

A workup on an ill child revealed low levels of om- plement C3 in her blood. Which one of the following presentations did this child most likely manifesti (A) Chronic eczema (B) Immune hemolytic anemia (C) Incomplete recovery from viral infections (D) Poor response to vaccination (E Recurrent infections with extracellular bacteria Vaccination

(E Recurrent infections with extracellular bacteria

Which one of the following represents the mecha- nism by which immune complexes (ICs) are normally cleared from the circulation? (A) ICs are solubilized by C3a (B) ICs are solubilized by C5a (C) Factor I releases complement-bound ICs to bind with complement receptors found on splenic/ hepatic neutrophils (D) Red blood cells capture ICs from blood via Fc receptors (E) C3b solubilizes ICs and attaches to red blood cells via complement receptors

(E) C3b solubilizes ICs and attaches to red blood cells via complement receptors

Which of the following is the site at which lym- phocytes can leave the blood and gain entry into the lymph nodes and what lymphocyte cell surface pro- tein mediates such access? (A) Lymphoid follicle: CD4 (B) Germinal center: CD62L (L-selectin) (C) Lymphoid follicle: CD621 (L-selectin) (D) Periarterial lymphatic sheath (PALS): CCR7 (E) High endothelial venules (HEV): CD62L (L-selectin)

(E) High endothelial venules (HEV): CD62L (L-selectin)

Macrophages recognize microorganisms through the interaction of microbial substances with what type of receptors on macrophages? (A) Antigen receptors (B) Complement receptors (C) Fc receptors (D) Membrane immunoglobulin (E) Pattern recognition receptors

(E) Pattern recognition receptors

Positive selection in the thymus occurs when thy- mocytes express functional versions of which critical molecule? (A) CD28 (В) Fe receptor (C) MHC class ! (D) MHC class II (E) T-cell receptor (TCR)

(E) T-cell receptor (TCR)

17 Which cells are the source of interleukin-4, -5, -10, and -13? (A) B cells (B) Macrophages (C) Mast cells (D) Thl cells (E) Th2 cells

(E) Th2 cells

A 47-year-old woman developed toxic shock follow- ing infection with a strain of Staphylococcus aureus that produced toxic shock syndrome toxin (TSST)-1. toxin binds directly to MHC Class II molecules on macrophages and which molecule on T cells? (A) CD3 (B) CD40 ligand (C) IC) Fas ligand (D) The gamma chain of the IL-2 receptor (E) The variable beta portion of the T-cell receptor

(E) The variable beta portion of the T-cell receptor

36 Antigen receptors on T and B cells share which similar feature? ( A) Affinity maturation occurs following antigen recognition for both receptor types (B) Interaction with MHC molecules is required for antigen recognition by both receptor types (C) The constant regions of both receptor types are identical (D) The specificity of both receptor types is determined following exposure of mature cells to antigen (E) The variable portions of both receptor types are generated by random recombination of genes

(E) The variable portions of both receptor types are generated by random recombination of genes

20 Which immune system cell is primarily responsible for the formation of granuloma in the lungs of tuber- culosis patients? (A) Cytotoxic T cells (B) Dendritic cells (C) Eosinophils (D) Natural killer cells (E) Thl cells

(E) Thl cells

A 34-year-old inmate presented to the prison clinic with fever, cough, and night sweats. Tuberculosis was suspected and PPD (purified protein derivative) was injected intradermally. A skin reaction characterized by erythema and induration developed at the injec- tion within 2 days. Which cell type is primarily responsible for reacting to the PPD and releasing mediators that resulted in the skin manifestation? (A) Endothelial cells (B) Keratinocytes (C) Langerhans cells (D) Mast cells (E) Thl cells

(E) Thl cells

5.3. Double-stranded RNA-dependent protein kinase mediates the action of A. chemokines. B. complement. C. defensins. D. natural killer cells. E. type l interferons.

(IFN) action, the first line of defense against viral infection. E. type l interferons.

pancreatic cytokine is certain Jumor 24-year-old airway secondary Her significant facial that The ing, which suddenly without and for 2 deficiency involving nent AKLinhibitor (B) (C) (D) (E)

A c1 inhibitor

Which of the following cells are important effector cells in allergic reactions? A. Basophils B. Dendritic cells C. Lymphocytes D. Monocytes E. Neutrophils

A. Basophils

7.8. Which of the following is a primary lymphoid organ? A. Bone marrow B. Lymph node C. Peyer's patch D. Spleen E. Tonsil

A. Bone marrow

1.2. Natural killer cells assess whether other cells are abnormal by detecting types surface-associated A. MHC class I molecules. B. nonself molecules. C. pathogen-associated molecular patterns. pattern recognition receptors. E. somatically generated cell surface receptors.

A. MHC class I molecules.

The basic structure of a Tcell receptor consists of A. a membrane-bound aß or yð heterodimer. B. a complex of disulfide-linked heavy and light chains. C. covalently linked CD3 and CD247 molecules. D. peptide-MHC complexes. E. soluble antigen-binding homodimers.

A. a membrane-bound aß or yð heterodimer.

The classical pathway of complement begins with A. activation of C1. B. cleavage and activation of C4, C2, and C3. C. IgA binding to a specific epitope. D. initiation of membrane attack complex formation. E. production of C3 convertase.

A. activation of C1.

A 76-year-old man is diagnosed with Escherichia coli septicemia. The initial immune response to E. coli (gram-negative bacteria) will include A. binding by LPS-binding proteins and delivery to receptors on macrophages. B. formation of specific somatically generated receptors to bind E. coli. C. generation and secretion of specific antibodies recognize E. coli. D. production of E. coli-specific cytokines by lymphocytes. E. stimulation of killer activation receptors on NK cells.

A. binding by LPS-binding proteins and delivery to receptors on macrophages.

5.5. The alternative complement pathway is initiated by A. cell-surface constituents that are recognized as foreign to the host. B. mannose-containing residues of glycoproteins on certain microbes. C. stimulation of killer activation receptors on NK cells. D. the formation of antibody-antigen complexes. E. toll-like receptor binding to pathogen-associated molecular patterns.

A. cell-surface constituents that are recognized as foreign to the host.

7.5. Lymph nodes have two main regions: the A. cortex and medulla. B. lymph and cortex. C. reticulum and cortex. D. Iymph and medulla. E. reticulum and medulla.

A. cortex and medulla.

Which of the following molecules is expressed by a mature T cell that functions as a helper T cell? A. CD4 B. CD8 C. GlyCAM-1 D. IgA E. IgG

A.CD4 CD4* T cells are also called T-helper cells.

2.5. Antibody mediated recruitment of macrophages occurs through action of A. complement receptors. B Fc receptors. C. killer activation receptors. D. pattern recognition receptors. E. toll-like receptors.

B Fc receptors.

4.8. Three days ago, an otherwise healthy 17-year-old boy sustained a skin laceration during a lacrosse match. Yesterday, he complained of mild "flulike" symptoms. This morning, he became suddenly ill with a fever, general muscle aches, and dizziness; then he lost consciousness. On arrival in the emergency department, he had a temperature of 37,8°C and a heart rațe of 136 beats per minute. His blood leukocyte count was 22,000 cells per ul (reference range: 4,500 to 12,500 per ul). The predominant cell type(s) in this patient's blood is/are most likely A. B lymphocytes. B) juvenile and mature neutrophils. (C)monocytes and macrophages. D. natural killer cells. E. Tlymphocytes.

B) juvenile and mature neutrophils.

h humans, MHC class Il molecules are expressed by A all nucleated cells. B. B cells, dendritic cells, and macrophages. C. erythrocytes. D. mast cells. E. naïve T cells.

B. B cells, dendritic cells, and macrophages.

4.5. Which of the following cells sample their extracellular environment by macropinocytosis? A Basophils B. Dendritic cells Eosinophils D. Macrophages E. Neutrophils

B. Dendritic cells

4.1. Which of the following types of cells are notable for their presence at the sites of helminth infections? A. Basophils B. Eosinophils C. Lymphocytes D. Monocytes E. Neutrophils

B. Eosinophils

1.5. Immunologic memory refers to A. activation of phagocytic cells to ingest microbial invaders. B. changes in adaptive immune responses with subse- quent encounters with antigen. C. constancy of the response of the innate immune response to a particular microbe. D. recognition of pathogen-associated molecular patterns by pattern recognition receptors. stimulating a defective host cell with reduced MHC I molecules to commit suicide.

B. changes in adaptive immune responses with subse- quent encounters with antigen.

4.9. Lymphoid lineage cells A. are the most numerous leukocyte population. B. consist of B, T, and NK cells. C. contain conspicuous cytoplasmic granules. D. differentiate from myeloid cell precursors. E. phagocytize debris and foreign cells.

B. consist of B, T, and NK cells.

The classical pathway of complement functions to A. cleave immunoglobulins into Fc fragments. B. facilitate destruction of microbes. C. recognize specific epitopes on microbes. D. regulate lymphocyte development. E. trigger histamine release,

B. facilitate destruction of microbes.

4.2. Natural killer cells are members of which of the following families of leukocytes? A. Basophils B. Eosinophils C Lymphocytes D. Monocytes E. Neutrophils

C Lymphocytes

1 Which of the following cytokines supports prolifera- tion and differentiation of developing ymphocytes in the primary lymphoid tissue? (A) Interleukin-1 (B) Interleukin-4 (C)Ihterleukin-7 D) Interleukin-12 (E) Interleukin-18

C interleukin

Which of the following molecules expressed on the surface of mature CD4* cells? A. B-cell receptor B. CD10 C. CD3 D. CD8 E. CD19

C. CD3

T-cell receptors, when coexpressed with CD8 mole- cules, are restricted to recognizing and binding peptide fragments associated with A. CD3 molecules. B. CD4 molecules. C. MHC class I molecules. D. MHC class Il molecules. E. MHC class III molecules,

C. MHC class I molecules.

2.4. Natural killer (NK) cells lyse Epstein-Barr virus-infected B cells with deficient MHC I expression. The NK receptors that initiate the lytic activity are A. complement receptors. B. Fc receptors. C. killer activation receptors. D. killer inhibition receptors. E. monomeric immunoglobulin receptors.

C. killer activation receptors.

Epitope-specific receptors of T lymphocytes are found A. aseither cytosolic or membrane-bound proteins. B. in blood plasma, lymph, and other secretory fluids. C. on the surface of plasma cells. D. as transmembrane polypeptides. E. in the nuclear lipid bilayer.

C. on the surface of plasma cells.

2.8. Cells of the immune system are triggered by the binding of surface receptors. In general, the action taken is determined by A. a single receptor per cell. B. a single type of receptor found on all cells. C. the integration of signals generated by multiple receptors on single cells. D. multiple receptors that bind soluble ligands only. E nonspecific receptors capable of binding a wide array of ligands.

C. the integration of signals generated by multiple receptors on single cells.

The primary lymphoid organs are those in which A. adaptive immune responses are usually initiated. B. filtration devices remove foreign matter. C. large numbers of circulating leukocytes make contact with one another. D. lymphocytes undergo their initial differentiation. E. pattern recognition receptors bind antigens.

D. lymphocytes undergo their initial differentiation.

4.6. Red blood cells are derived from A. granulocytic tineage cells. B. lymphocytic lineage cells. C monocytic lineage cels. D. myeloid lineage cells. E. thrombocytic lineage cells.

D. myeloid lineage cells.

B lymphocytes synthesize and express immunoglobulin A. containing multiple epitope specificities. B. in cytoplasmic phagosomes. C. in membrane complexes also containing CD3. D. on their cell membrane surface. E. only after leaving the bone marrow.

D. on their cell membrane surface.

A 16-year-old boy has acute appendicitis (infection of the appendix). Which of the following blood cells is most likely to increase in number as a result of his condition? A. Basophils B. Eosinophils C. Lymphocytes D. Monocytes E Neutrophils

E Neutrophils

The thymus is the site of initial differentiation for A. B cells. B. erythrocytes. C. hematopoietic stem cells. D. NK cells. E. T cells.

E. T cells.

Pattern recognition receptors bind to A. B and T lymphocytes. B. host cell-associated molecules. C. MHC I molecules. D. natural killer cells. E. pathogen-associated molecular patterns.

E. pathogen-associated molecular patterns.

1.4. Somatically generated receptors found on B and Tlymphocytes are A. bound only to MHC I molecules. B. encoded in the germline to recognize pathogen- associated molecular patterns. C. first produced after an initial encounter with nonself. D. identical among individuals. E. randomly generated during development.

E. randomly generated during development.

Positive selection refers to A. the ability of single positive cells to bind both MHC class I and II. B. cortical thymocytes' acquisition of TCR. C. migration of stem cells to the thymus to become T cells. D. programmed cell death of single positive T cells. E. recognition of MHC by CD4*CD8* thymocytes.

E. recognition of MHC by CD4*CD8* thymocytes.

Migration of a B lymphocyte to specific sites (such as a lymph node) is dependent in part on the A. antibodies. B. CD8. C. CD3. D. complement. E. selectins.

E. selectins.

6.2. Antibodies (immunoglobulins) A. are synthesized and secreted by both B and T cells. B. bind to several different epitopes simultaneously. C. contain four different light chain polypeptides. D. recognize specific epitopes together with self molecules. E. tag antigens for destruction and removal.

E. tag antigens for destruction and removal.

A 45-year-old AIDS patient was enrolled in a drug development study. As part of the study, he underwent anergy skin testing. He was inoculated intradermally with candidal and mumps virus antigens. No reaction was demonstrable after 48h. What is the most likely explanation for this? (A) Antiretroviral drugs are known to interfere with (B) He is this type of test has neutropenia and cannot control the growth of Candida (C) He lacks antibodies to both Candida and mumps virus (D) His CD8 cells are not being activated due to decreased CD4 cell numbers (E) His Thl cells are unable to carry out a delayed type hypersensitivity reaction

His Thl cells are unable to carry out a delayed type hypersensitivity reaction

1.6. Influenza viruses infect humans and elicit an immune response that is often insufficient to protect the indi- vidual from sickness or death. Which of the following structures are on influenza viruses, allowing them to be recognized by the human immune system? A. MHC I molecules B. MHC I molecules C. Pathogen-associated molecular patterns D. Pattern recognition receptor E. Somatically generated receptors

MHC I and Il molecules are present on all nucleated host cells but not viruses.

5.1. Pathogen-associated molecular patterns (PAMPS) allow B and T lymphocytes to recognize bacteria and destroy them. B. are cysteine-rich peptides that form channels in bacterial membranes. (C) are recognized by pattern recognition receptors of the innate immune system. D. closely resemble host cell surface proteins and sugars. E. induce secretion of interferons by virally infected host cells.

are recognized by pattern recognition receptors of the innate immune system.

4.7. A subset of which of the following of these undergoes further differentiation within the thymus? A. Basophils B. Eosinophils c. Lymphocytes D. Monocytes E. Neutrophils

c. Lymphocytes

1.1. Immune recognition of molecules belonging to self important to A. activate natural killer cells of the innate immune system. B. determine the safety of interacting with the molecule. C. induce somatic generation of a B- or T-lymphocyte receptor for the molecule. D. stimulate binding by pattern recognition receptors. E. trigger attack on the cell expressing the molecule.

determine the safety of interacting with the molecule.