immunology practice test 3

Helper T cells that have been activated to differentiate into effector cells interact with antigen stimulated B lymphocytes at: Centers of lymphoid follicles. Edges of lymphoid follicles. Germinating centers of lymphoid follicles. The site of microbial invasion.

Edges of lymphoid follicles.

The CD8+ cytolytic T lymphocyte (CTL) uses different mechanisms to kill the target cell. Which of the following intracellular molecules activate the Caspase cascade: Caspase-receptors Fas receptors Granzymes Perform

Granzymes

Loading of antigen peptides into human MHC class II peptide binding pocket is mediated by which of the following molecules? MHC class I proteins Transporter Associated with Peptide processing (TAP) HLA-DM Proteasome Class II Invariant Chain (CLIP)

HLA-DM

Complement activation, endothelial damage, inflammation and thrombosis in response to a graft insertion within minutes is considered: Hyperacute rejection Acute rejection Subacute rejection Chronic rejection

Hyperacute rejection

Immunoglobulin's heavy chain class switching results in producing different classes of antibodies to effectively neutralize the microbes and toxins. Mucosal immunity is best carried on by: IgA IgD IgE IgG subclasses (IgGi, IgG3) 1gM

IgA

Little Johnny was playing in the backyard, suddenly he was stung by a bee, immediately there was reddness and swelling and an anaphylaxis shock. This reaction is an example of: IgE-mediated hypersensitivity. Antibody-mediated or cytotoxic hypersensitivity. Immunocomplex-mediated hypersensitivity. Cell-mediated hypersensitivity.

IgE-mediated hypersensitivity.

Which of the following best describes 'Type I Hypersensitivity'? Immediate hypersensitivity which is caused by the release of mediators from mast cells triggered by antigen cross-linking of immunoglobulin E bound to IgE receptors. Antibodies specific for cell or tissue antigens can cause damage by activating complement and engaging phagocytes. Antibody-antigen complexes (immune complexes) deposit in blood vessels, causing inflammation and tissue injury. Reactions of T lymphocytes, often against self antigens in tissues, can cause tissue damage.

Immediate hypersensitivity which is caused by the release of mediators from mast cells triggered by antigen cross-linking of immunoglobulin E bound to IgE receptors.

The life cycle ofHIV consiss ofthe following sequential steps: Infection of Cells, production of viral DNA and its integration into the host genome, expression of viral genes, and production of viral particles Infection of Cells, production of viral RNA and its integration into the host genome, expression of viral genes, and production of viral particles Infection of Cells, expression of viral genes, production of viral DNA and its integration into the host genome, and production of viral particles Infection of Cells, production of viral RNA, expression of viral genes, and production of viral particles Infection of Cells, production of viral DNA, and production ofviral particles

Infection of Cells, production of viral DNA and its integration into the host genome, expression of viral genes, and production of viral particles

Which of the following statements best describes the T-dependent antibody response? It is the response of B lymphocytes to a protein antigen and characterised by isotype-switched, high-affinity antibodies;memory B cells, long lived plasma cells. It is the response ofB lymphocytes to a polysaccharide antigen and characterised by isotype-switched, high-affinity antibodies; memory B cells, long lived plasma cells. It is the response of B lymphocytes to a protein antigen and characterised by mainly 1gM, low-affinity antibodies; short- lived plasma cells. It is the response of B lymphocytes to a polysaccharide antigen and is characterised by mainly 1gM, low-affinity antibodies; short-lived plasma cells.

It is the response of B lymphocytes to a protein antigen and characterised by isotype-switched, high-affinity antibodies;memory B cells, long lived plasma cells

Effector T cells migrate to sites of infection because they express adhesion molecules and chemokine receptors that bind to ligands expressed or displayed on vascular endothelium. The initial weak adhesion of the effector T lymphocytes to the vascular endothelium involves which molecule on the effector T lymphocyte? Leukocyte Function-associated Antigen 1 (LFA-1) L-selectin Chemokine receptor CCR7 F- and P-selectin Ligands F. Chemokine receptor CXCR5

L-selectin

During the phases ofan adaptive immune response, the clonal expansion and differentiation ofthe lymphocytes associate with which of the following phases? Antigen recognition Lymphocyte activation Antigen elimination Contraction (homeostasis)

Lymphocyte activation

The activation ofthe B lymphocytes following contact with the antigen involves all of the following molecules EXCEPT: Membrane 1gM and IgD Iga and Igf3 signal transduction molecules C3d complement receptor type 2 (CR2) Pattern recognition receptors, e.g., TLR MHC class II molecules

MHC class II molecules

All ofthe following cells are effector cells ofthe adaptive immune system EXCEPT: Cytolytic T lymphocytes Helper T lymphocytes Macrophages cells Plasma cells Regulatory T lymphocytes

Macrophages cells

The terminal pathway of the complement activation results in the production of: C3 convertase. C5 convertase. Mannan-binding Lectin-associated Serine Protease (MLSP) Membrane-Attack-Complex (MAC).

Membrane-Attack-Complex (MAC).

X-linked Agammglobinemia is characterized by: Increased B lymphocyte numbers Increased secretion of 1gM and lack of secretion of IgG Increased T lymphocytes numbers Severe decrease or absence of antibodies

Severe decrease or absence of antibodies

Immunological tolerance to different self antigens may be induced when developing lymphocytes encounter these antigens in the generative (central) lymphoid organs. One of mechanisms of this tolerance is the generation of Regulatory lymphocytes which takes place during the development of: The Helper T lymphocytes The Cytolytic T lymphocytes The B lymphocytes The Plasma cells Both, the B lymphocytes and the T lymphocytes

The Helper T lymphocytes

The antigen recognition on the T cells is mediated by: Variable (V) regions of heavy and light chains of membrane immunoglobulins The Variable (V) regions of Alpha and Beta chains Proteins (Igct and 1gJ3) associated with membrane Ig Proteins (CD3 and ) associated with the receptor.

The Variable (V) regions of Alpha and Beta chains

Allergists sometimes treat patients by injecting them with the very allergen they are sensitive to it. Why? If the allergen is present in high enough titers, it may be mistaken for a self protem and ignored. The allergen may trigger the production of IgG, and thus prevent IgE-triggered responses. An injection into muscle will divert the immune response from the upper respiratory tract. This prevents the allergen from denaturing as it crosses an epithelial barrier. These guys are quacks and will try anything if they can get money for it.

The allergen may trigger the production of IgG, and thus prevent IgE-triggered responses.

The antigen binding cleft ofMajor Histocompatibility Complex (MHC) Class II molecules is formed of: The o1 and ct2 domains ofthe Alpha chain. The f31 and 2 domains of the Beta chain. The alpha1 and beta1 domains of the Alpha and Beta chains respectively. The ct2 and f32 domains of the Alpha and Beta chains respectively. F. A cd and a f32-microglobulin.

The alpha1 and beta1 domains of the Alpha and Beta chains respectively.

Pathogen-associatedmolecularpatterns(PAMPs): Are found on many microorganisms. Are restricted to Gram-positive bacteria. Are restricted to Gram-negative bacteria. Are restricted to toxin-secreting bacteria.

are found on many microorganisms

Central tolerance by apoptosis of immature B lymphocytes which may recognize self-antigen takes place in the: Bone marrow Lymph nodes follicles The Spleen follicles The Thymus gland The Periarteriolar Lymphoid Sheath (PALs) in the spleen.

bone marrow

The DIRECT effector functions of antibodies include all of the following EXCEPT: Neutralization ofmicrobes and toxins. Opsonization and phagocytosis of microbes. Antibody-dependent Cellular Cytotoxicity (ADCC). Complement activation. Inflammation.

complement activation

Which B cell subset makes antibody responses to protein antigens and requires T cells help? Follicular B cells Marginal zone B cells B-i B cells Memory B cell

follicular B cells

The CD8+ cytolytic T lymphocyte (CTL) uses different mechanisms to kill the target cell. Caspase-activating granules are delivered to target cells through: A. Caspase-receptors B. Fas receptors C. Granzymes D. Perforin

granzymes

Antigens are molecules that binds to an antibody or a T-Cell Receptor. cells that cause organ graft rejection. proteins found in the blood. cells that cause antibody formation. substances that kill invading bacteria.

molecules that binds to an antibody or a T-Cell Receptor.

The signaling functions on the B lymphocytes is mediated by the Variable (V) regions of heavy and light chains of membrane immunoglobulins. Variable (V) regions ofalpha and beta chains. proteins (Iga) and Igb) associated with membrane iimunoglobulins. proteins (CD3 and )

proteins (Iga) and Igb) associated with membrane iimunoglobulins.

Major Histocompatibility Complex (MHC) class II molecules are expressed on all the following cells EXCEPT: A. B lymphocytes B. Macrophages C. T lymphocytes Dendritic cells Kupffer cells

t lymphocytes

Activated T Lymphocytes express high affinity Interleukin -2 Receptor (IL-2R) complex, which is composed of which of the following chains? a and beta chains beta and yc chains a and yc chains a and b and yc chain

a and b and yc chain

Which one of the following is NOT true of the gene segments that combine to make up a heavy-chain gene? Many 'V region segments are available. Several 'J segments and several 'D' segments are available. 'V', D', and 'J' segments combine to encode the antigen-binding site. A 'V' segment and a 'J' segment are preselected by an antigen to make up the variable-region portion ofthe gene.

A 'V' segment and a 'J' segment are preselected by an antigen to make up the variable-region portion ofthe gene.

CD4O Ligand (CD 1 54) is expressed by which of the following? B lymphocytes Dendritic cells Resting T lymphocytes Activated T lymphocytes All leukocytes

Activated T lymphocytes

Peripheral tolerance in T lymphocytes may take place by which ofthe following mechanism(s)? Cell-intrinsic anergy Suppression by regulatory T cells Deletion (apoptotic cell death) All of the above

All of the above

Cytokines are produced by cells ofthe immune system, in response to various physiological stimuli, their function (s) is (are) to: modulate cell function through subsequent cell differentiation or cell proliferation. facilitate target cell apoptosis. facilitate cytokine release by same or other cells. cause histamine release. All of the above.

All of the above.

Inherited risk for most autoimmune diseases is attributable to multiple gene loci, the risk of development of ankylosing spondylitis, an autoimmune diseases of the spine, is associated with: Alleles ofthe major histocompatibility complex (MHC) locus. Non major histocompatibility complex (MHC) genes. Single-gene defects. All of the above.

Alleles ofthe major histocompatibility complex (MHC) locus.

The initiation ofT cell responses requires multiple receptors on the T cells recognizing ligands on APCs. The MHC molecule located around the peptide-binding cleft is recognized by the: Leukocyte Function-associated Antigen 1 (LFA-1) CD4 or CD8 molecules. C. CD28 CD3 and Zeta () molecules. Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4)

CD4 or CD8 molecules

All of the following statements about the T-cell antigen receptor(S) are true EXCEPT: They are membrane-bound heterodimer chains. Antigen recognition is mediated by the Variable (V) regions of the heavy and light chains They are the recognition element of the cell-mediated arm of the immune system They recognizes antigen fragments via the Variable (V) regions of the Alpha and Beta chains

Antigen recognition is mediated by the Variable (V) regions of the heavy and light chains

Host cytolytic T lymphocytes against tumors are often induced by recognition of tumor antigens on host which ingest tumor cells or their antigens and present the antigens to T cells? Antigen-presenting cell Folicular B cells Marginal B cells Natural Killer Cells

Antigen-presenting cell

Captain America is a hero, while fighting against crime he was wounded and brought to hospital. He needed blood transfusion. During this transfusion, Captain America start to sufer from fever, hypotension, anxiety, and red-coloured urine. You, being a smart Aggie physician and took Dr. Omran's immunology class, diagnosed the situation as a Mismatched Blood Transfusion Reaction and you took the appropiate methods to save Captain America. Now you explain this phenomenon to the young Longhorn intern, so you describe this reaction as: An antibody-mediated/cytotoxic hypersensitivity. A hyperacute graft rejection due to pre-existing antibodies in the host circulation against blood group antigens. A hyperacute graft rejection due to mismatching ofMHC in both ofthe blood group antigens. Both, a hyperacute graft rejection and an antibody-mediated/cytotoxic hypersensitivity.

Both, a hyperacute graft rejection and an antibody-mediated/cytotoxic hypersensitivity.

Analysis of cytokine production by helper T (Th) cells has revealed that functionally distinct subsets of CD4+ T cells exist that produce different cytokines. The IL-4, IL-5, and IL-13 are the signature cytokines of: CD4+ Effector T Lymphocytes Type 1 (TH 1) CD4+ Effector T Lymphocytes Type 2 (TH2) CD4+ Effector T Lymphocytes Type 17 (TH17) Follicular Helper T lymphocyte

CD4+ Effector T Lymphocytes Type 2 (TH2)

Human Immunodeficiency Virus (HIV), the causative agent ofAcquired Immunodeficiency Syndrome (AIDS) mainly affects the B lymphocytes and macrophages. CD4+ T lymphocytes and macrophages. CD8+ T lymphocytes and macrophages. Immature CD4+ T lymphocytes and macrophages. CD4+ T lymphocytes, CD8+ T lymphocytes and macrophages.

CD4+ T lymphocytes and macrophages.

The effector CD4+ cells (TH1) that recognize macrophage-associated antigens activate the macrophages by: A. B7 and CD28 interaction CD4OL - CD4O interaction and IFN'y CD4OL - CD4O interaction and IL-i and IL-12 CD4OL - CD4O interaction and IL-4 and IL-5

CD4OL - CD4O interaction and IFN'y

The tuberculin test, poison Ivy, and Type I diabetes are delayed type hypersensitivity reactions. This makes them: IgE-mediated hypersensitivity. Antibody-mediated or cytotoxic hypersensitivity. Immunocomplex-mediated hypersensitivity. Cell-mediated hypersensitivity.

Cell-mediated hypersensitivity.

All ofthe following may be considered as tumor antigens EXCEPT: Products of diverse mutated genes. Products of oncogenes or mutated tumor suppressors. Chemical carcinogens. Aberrently expressed proteins. Oncogenic viral antigens.

Chemical carcinogens.

During the inflammatory process, leukocyte extravasation goes through the following phases: Rolling adhesion, Tight adhesion, Transmigration, and Chemoattraction. Leukocyte migration to inflammatory site is the direct involment of: Selectin adhesion molecules. Chemokine activation. Cytokine activation. Integrm adhesion molecules.

Chemokine activation.

The Transporter Associated with Antigen Processing (TAP) is associated with the: Class I MHC pathway of intracellular processing of protein antigens Class II MHC pathway of intracellular processing of protein antigens Complement Cascade Clotting Cascade

Class I MHC pathway of intracellular processing of protein antigens

A previously healthy 8-year-old boy is infected with an upper respiratory tract virus for the first time. During the first few hours of infection, which one of the following events occurs? The adaptive immune system responds rapidly to the virus and keeps the viral infection under control. The innate immune system responds rapidly to the viral infection and keeps the viral infection under control. Passive immunity mediated by maternal antibodies limits the spread of infection. B and T lymphocytes recognize the virus and stimulate the innate immune response. The virus causes malignant transformation of respiratory mucosal epithelial cells, and the malignant cells are recognized by the adaptive immune system.

The innate immune system responds rapidly to the viral infection and keeps the viral infection under control.

All ofthe following statements about the B-cell antigen receptor(S) are true EXCEPT: They are membrane-bound antibodies They may be secreted into the plasma by the B-cell They are the recognition element of the humoral arm of the immune system They recognizes antigen fragments via the Alpha and Beta chains Antigen recognition is mediated by the Variable (V) regions of the heavy and light chains

They recognizes antigen fragments via the Alpha and Beta chains

All of the following are true with respect to IgE molecules, EXCEPT which one? They are the principal immunoglobulin class involved in allergic reactions. They are involved in mediating anti-parasitic immune responses. They will cross the placenta and fix complement. They can mediate the release of histamine and other chemical effectors.

They will cross the placenta and fix complement.

The following statements are true about peripheral or secondary lymphoid tissues EXCEPT: Refer to the tonsils, Peyer's patches, and spleen Refers to activated lymph nodes along the lymphatics Where B and T lymphocytes mature Where naive B and T lymphocytes come in contact with the antigens

Where B and T lymphocytes mature

DiGeorge Syndrome (which is a congenital disease) is associated with: an increase in the B lymphocytes to compensate for the absence of T lymphocytes. an increase in the T lymphocytes to compensate for the absence ofB lymphocytes. absence of the thymus gland. absencterm-11e of spleen.

absence of the thymus gland

The activation of the complement cascade will result in all the following EXCEPT: Opsonization of pathogens. Activation of T lymphocytes. Activation of B lymphocytes. Killing/destruction of pathogens. Recruitment of inflammatory cells.

activation of t lymphocytes