Immunology Exam 2

A plasma cell secretes A) antibody of a single specificity similar to the specificity of the BCR on the parent B-cell B) antibody of 2 antigen specificities C) the antigen it recognizes D) multiple antibody classes E) perforin & granzymes

A

A study of immune responses is conducted. Antigen and antibody are mixed in sufficient proportions to produce antigen-antibody complexes. When these complexes form, there is inhibition of an immune response. Which of the following cells is most likely receiving feedback inhibition by these complexes? A) B cell B) eosinophil C) mast cell D) NK cell E) neutrophil

A

Both B and T cells are lymphocytes that participate in the adaptive immune response. However, the receptors expressed by B and T cells differ in significant ways. What is one difference between antigen recognition by B and T cells? A) B cells can recognize extracellular or cell surface antigens of any molecular type, while T cells can only recognize peptide fragments of proteins displayed by a specific cell surface molecule B) B cells secrete antigen receptors, but do not express antigen receptors on their membranes, while T cells can both secrete antigen receptors and express antigen receptors on their membranes. C) B cells can only recognize antigens that have been processed inside cells before display on the cell surface, while T cells can only recognize intact cell surface or intact secreted molecules. D) B cell antigen receptors are lipid molecules, while T cell antigen receptors are proteins

A

CDR3 of the heavy chain of an antibody is coded by A) D-J gene segments B) V-J gene segments C) V-D-J gene segments D) V-D gene segments

A

Class switching of antibodies involves A) change of one CH gene segment to a different CH gene segment B) change of κ chain to λ chain C) change of one complete heavy-chain polypeptide to another D) change of λ chain to κ chain

A

Co-receptor on B-cell able to down regulate B-cell activation A) CD22 B) CTLA-4 C) Fc (CD16) D) CD4 E) CD8

A

Enzyme that promotes antibody class switching through its cytidine deaminase activity A) AID B) granzyme C) Artemis D) TdT E)RAG F) JAK

A

In the light of clonal selection theory, which of the following statements is false? A) upon second encounter of the antigen, B cells can change their specificity B) the specificity of an antibody molecule is determined prior to its encounter with antigen C) An antigen entering the host body simply "selects" & "switches on" a specific B cell D) One B cell produces antibody molecules of a single specificity

A

Isotope switching cannot occur from IgG to A) IgM B) IgA C) IgE D) All of the above

A

N-region insertion during VDJ joining is associated with: A) terminal deoxynucleotidyl transferase B) NK cell antigen receptors C) proteasome D) lysozyme E) heat shock proteins

A

T-cell receptor that interacts with CD80/86 of activated macrophages, serving as signal 2 during T-cell activation. A) CD28 B) CD3 C) Fc (CD16) D) CD4 E) CTL4-A

A

The clonal selection theory of antibody diversity says A) B cell precursors randomly rearrange variable coding parts of antibody genes. Afterwards, antigen binds to a clone with specific membrane antibody, resulting in differentiation to antibody secreting plasma cells B) The antigen causes a nonspecific clone of B lymphocytes to proliferate and secrete antibody molecules capable of binding to any foreign antigen C) Antigen causes the growth of a clone of lymphocytes which then rearrange DNA, creating a gene coding for a specific antibody D) A clone of macrophages with specific receptor for antigen phagocytoses antigen, then rearranges DNA to generate specific antibody-coding genes

A

The process through which primary transcripts can be spliced to generate membrane-bound and secreted forms of a heavy-chain polypeptide is called A) alternative splicing B) somatic hypermutation C) combinatorial association D) allelic exclusion

A

Which immune cell is responsible for the quickest release of histamine that causes the red itchy welts associated with allergies? A) mast cell B) lymphocyte C) eosinophil D) basophil

A

Which of the following is not involved in specific immunity? A) neutrophil B) T cell C) Plasma cell D) B cell E) memory cell

A

Which of the following processes is used to increase antibody diversity following exposure of naive B-cells to antigen? A) Somatic hypermutation B) Somatic recombination C) Junctional diversity D) random assortment of heavy and light chains E) allelic exclusion

A

Which of the following statements does not apply to IgG? A) appears early in the primary immune response B) neutralizes viruses & bacterial toxins C) can fix complement D) crosses the human placenta E) opsonizes bacteria

A

Which one of the following cell will not have alpha-1 gene segment (that codes for IgA1) in their germ-line DNA? A) IgE-secreting plasma cell B) IgM-secreting plasma cell C) Stem Cell D) Immature B Cell

A

A B cell expresses antibodies of more than one specificity. Which of the following events do you think did not occur? A) V-D-J recombination B) allelic exclusion C) somatic hypermutation D) combinatorial pairing

B

A B-cell is able to make cell-surface and secreted versions of antibody using A) different gene pools B) differential splicing C) different heavy chain class but the same light chain D) different light chain class but the same heavy chain E) F(ab^1)2 fragments

B

A chromosome on which T-cell receptor alpha chain gene rearrangement has occurred lacks which of the following gene segments: A) Joining (J) B) Diversity (D) C) Variable (V) D) Constant (C) E) TCR beta chain

B

Enzyme released by NK cells that passes through holes formed in the plasma membrane of target cells by perforin. A) AID B) granzyme C) Artemis D) perforin E) JAK

B

Epstein Barr virus (EBV) infects endothelial cells and B cells. About half of us are infected by the virus while very young, and do not suffer disease. Around half of individuals who avoid the virus while young are infected in the teenage years and develop a disease called mononucleosis. In this disease, lymph nodes swell painfully as our immune system produces large numbers of lymphocytes to eliminate virus-producing cells. These lymphocytes are probably: A) B cells which produce antibody eliminating virus-infected cells B) Cytotoxic T cells to destroy virus-containing cells C) Helper T cells which stimulate B cell clonal selection D) Granulocytes which invade areas of virus production

B

In a study of antigen-antibody interactions it is observed that antibody binds to a specific antigen. There is a variable region of the immunoglobulin molecule that imparts specificity. This binding is most likely to occur through the action of which of the following parts of an immunoglobulin molecule? A) disulfide bond B) Fab region C) Fc portion D) heavy chain E) light chain

B

In mammals, which of the following does not contribute to the generation of antibody diversity? A) multiple germ-line gene segments B) gene conversion C) Combinational diversity D) Junctional Diversity

B

One enzyme that is not influenced in V(D)J rearrangement in an antibody molecules A) RAG-2 B) AID C) TdT D) RAG-1

B

Pollen grains inhaled by a child cause a severe asthmatic attack. This reaction could be because of A) IgD B) IgE C) IgA D) IgG

B

T cell surface receptors for antigen partly recognize A) cytokines B) MHC C) ADCC D) Antibody E) IL-2

B

The Fab region of an Ig is responsible for A) binding to NK cells B) binding to antigen C) binding to Fc receptors D) binding to macrophages E) the ability of Ig to cross the human placenta

B

The lack of an immune response to self is called A) autoimmunity B) tolerance

B

The molecules mediating signal transduction following antigen binding to cell surface immunoglobulin on a B-cell are called: A) Ig Fc B) Ig-alpha & Ig-beta C) MHC D) CD4 E) CD8

B

The percentage of human peripheral blood T-cells bearing a gamma delta T-cell receptor is A) 30-80% B) 5% C) 100% D) 0% E) only present during mycobacterial infections

B

What is the approximate number of D segment genes in the immunoglobulin heavy chain gene locus A) 40 B) 30 C) 9 D) 6 E) 1

B

Which of the following statements is false for recombination signal sequences? A) RSS are present on both sides of the D segment B) Presence of 2 conserved sequences- heptamer & spacer C) RSS is located on 3' side of the V gene D) RSS is located on 5' side of the J gene

B

After somatic hypermutation, the one characteristic of an antibody that changes is A) specificity B) molecular weight C) affinity D) solubility

C

Antigen-specific antibodies are readily detectable in serum following primary contact with antigen after A) 10 min B) 1 h C) 5-7 days D) 3-5 weeks E) only following a second contact w/ antigen

C

Enzyme with endonuclease activity that contributes to junctional diversity during VDJ joining by generating P nucleotides at the ends of cleaved hairpin DNA. A) AID B) granzyme C) Artemis D)TdT E) JAK F) RAG

C

Expectant parents now have the option to save their baby's "cord blood" (blood from the umbilical cord) immediately following birth. This cord blood can be transplanted into individuals whose blood has been damaged by diseases such as leukemia, Hodgkin's lymphoma, and sickle cell anemia. Saved cord blood is a perfect match for the baby it came from, and can also be useful in treating relatives of the baby. What cells should be harvested from the cord blood to best treat patients with blood diseases? A) erythrocytes (red blood cells) B) leukocytes (granulocytes, monocytes, & lymphocytes) C) stem cells

C

If a B cell clone began to produce antibody with altered binding strength and specificity for antigen, you would expect the mutation of the antibody gene to involve A) The variable region of the heavy chain or the constant region of the light chain B) The variable region of the light chain or the constant region of the heavy chain C) The variable regions of the light or heavy chains D) The constant regions of the light or heavy chains

C

IgA in mucus secretions A) has no J-chain B) has no secretory piece C) is dimeric D) cannot bind to viruses E) binds to NK cell

C

In an experiment, bacterial organisms are added to whole human blood. It is shown that the bacterial organisms become opsonized. The opsonized bacteria are observed to be phagocytized by neutrophils. Which of the following components of the immunoglobulin molecules on these bacteria is most likely to lead to phagocytosis? A) disulfide bond B) Fab region C) Fc portion D) heavy chain E) light chain

C

Junctional diversity increases sequence variation predominantly in this region of the Variable (V) region of an antibody. A) CDR1 B) CDR2 C) CDR3 D) CDR1, CDR2, & CDR3 E) none of the above

C

Receptor on NK cells used to recognize antibody molecules. A) CD28 B) CD3 C) Fc D) CD4 E) CD8

C

TCR co-receptor on T-helper cells that interact with MHC II A) CD28 B) CD3 C) Fc (CD16) D) CD4 E) CD8

C

The ability to produce billions of different antibodies in humans results from A) The presence of billions of complete antibody genes in B cells B) The fact that both T cells and B cells contain antibody genes C) The production of variable regions of light and heavy antibody genes by DNA rearrangement D) The fact that a single antibody gene produces an antibody capable of billions of different three-dimensional structures and the ability to combine with any antigen

C

The enzyme that is involved in increasing the affinity of an antibody is A) RAG-2 B) TdT C) AID D) RAG-1

C

The presence of which of the following membrane-bound antibodies is used as a marker of B-cell maturation? A) IgA B) IgM C) IgD D) IgE E) IgG

C

What is the term used to describe white blood cells migrating toward bacteria? A) zeiosis B) phagocytosis C) chemotaxis D) phototaxis

C

Which class of antibody is likely to play the greatest role in an individual developing puffy eyes and running noise after exposure to pollen? A) IgA B) IgD C) IgE D) IgM E) IgG

C

Which of the following best describes the difference in how B cells and cytotoxic T cells respond to invaders? A) B cells confer active immunity; cytotoxic confer passive immunity. B) B cells kill viruses directly; cytotoxic T cells kill virus infected cells. C) B cells remember pathogens and produce antibodies; cytotoxic T cells directly kill cells that are infected with pathogens. D) T cells remember pathogens and produce antibodies; cytotoxic B cells directly kill cells that are infected with pathogens.

C

Which of the following best describes the difference in how B cells and cytotoxic T cells respond to invaders? A)B cells confer active immunity; cytotoxic confer passive immunity. B) B cells kill viruses directly; cytotoxic T cells kill virus infected cells. C) B cells remember pathogens & produce antibodies; cytotoxic T cells directly kill cells that are infected with pathogens. D) T cells remember pathogens and produce antibodies; cytotoxic B cells directly kill cells that are infected with pathogens.

C

Which of the statements is not correct? A) IgG can cross the placenta B) J chain-deficient individuals will have a vulnerable mucosal surface C) a cell can synthesize IgG2 & then switch to IgG4 antibodies D) Immunoglobulin genes are un-rearranged in adipocytes

C

A newborn infant has circulating immunoglobulins derived from maternal circulation. By which of the following mechanisms has this infant attained this passive immunity from mother? A) Complement diffuses into the fetal circulation B) Fetal mast cells bind IgE C) Interleukin-2 induces CD4 cell proliferation D) Placental Fc receptors bind IgG E) Plasma cells cross the villi

D

Allergies result from the production of ______ directed against an antigen A) IgG B) IgA C) IgM D) IgE

D

During generation of diversity in the antibodies, which of the following enzymes does not require a template for the addition of nucleotides A) DNA ligase B) Activation-induced cytosine deaminase (AID) C) DNA polymerase D) terminal deoxynucleotidyl transferase (TdT)

D

Enzyme that adds non-templated N residues to the end of P residues A) AID B) granzyme C) Artemis D) TdT E) RAG

D

Junctional diversity could be generated by all of the following except A) N-additions B) P-additions C) Imprecise joining of V, (D), J segments D) Somatic hypermutation

D

RAG1 & RAG2 enzymes effect the recombination of A) VDJ to CH B) H to L C) CDR1 to CDR2 D) V to D E) VJ to C1

D

Switch region is 2 kbp sequence located upstream of each CH segment except A) Cα B) Cε C) Cμ D) Cδ

D

The T-cell receptor for antigen is A) derived from the immunoglobulin gene pool by alternative splicing B) tetramer C) homodimer D) heterodimer E) single chain molecule

D

The adaptive immune response includes B cells that secrete antibodies. Antibodies perform multiple functions to protect us from pathogens. Which of the following antibody functions does not depend on the binding of additional molecules or cells to the non-antigen binding end (Fc region) of an antibody molecule? A) Antibody-dependent killing of an infected cell by natural killer cells B) Opsonization of a microbe to enhance phagocytosis C) Complement-mediated lysis of a microbe D) neutralization of a bacterial toxin

D

The complementarity determining regions (CDRs) of the BCR: A) are restricted to light chains B) are in the constant part of the Ig molecule C) bind to Fc receptors D) are involved with antigen recognition E) occur at the C-terminal end of the Ig peptide chains

D

The primary RNA transcript of the κ chain contains rearranged: A) V-D-J gene segments B) V-J-C gene segments C) V-D gene segments D) V-J gene segments

D

Which cell type produces antibodies? A) Macrophages B) T-lymphocytes C) NK D) Plasma cells E) Eosinophils

D

Which of the gene segments do not contribute to the light chain of antibody molecules? A) J B) C C) V D) D

D

___________ are responsible for the production of antibody against free pathogens and soluble products from pathogens while ____________ destroy pathogen and virally infected cells and abnormal cells. A) Cytotoxic T cells, B cells B) Macrophages, T cells C) B cells, helper T cells D) B cells, cytotoxic T cells

D

the human heavy-chain and λ light-chain genes are located on _ & _ chromosomes, respectively A) 12, 22 B) 14, 2 C) 12, 2 D) 14, 22

D

A study is performed evaluating the effectiveness of vaccination to viral pathogens. Persons receiving vaccines have a greatly reduced incidence of complications with infectious diseases for a decade following immunization. Which of the following immune mechanisms is most likely to confer protection to these immunized persons? A) Antibody binding to mast cells B) Neutralizing antibodies C) Neutrophil chemotactic factors D) NK cell proliferation E) T cell stimulation

E

IgM: A) is usually of high affinity B) is most commonly tetrameric C) has the same number of constant domains as IgG D) is a weak bacterial agglutinator E) is the main class of 'natural antibodies'

E

In a clinical trial, polio vaccine is found to be most effective when administered orally. This oral vaccine is most likely to elicit which of the following protective immune responses? A) Antigen gathering by dendritic cells B) Binding of IgE to mast cells C) CD4 cell proliferation in gut-associated lymphoid tissue D) Increased memory B cells E) Mucosal IgA secretion

E

MHC Class 2 molecules bind to ______ and trigger ____ A) endogenous antigens, cytotoxic T cells B) exogenous antigens, cytotoxic T cells C) antibodies, B cells D) endogenous antigens, helper T cells E) exogenous antigens, helper T cells

E

Protein that recognizes RRS elements and is essential for joining of VDJ segments during immunoglobulin gene recombination. A) AID B) granzyme C) Artemis D) TdT E) RAG F) JAK

E

Recombination of V,D & J Ig gene segments A) only occur immature B cells B) only occur in light chains C) involves hep tamer-spacer-heptamer flanking sequences D) takes place by mRNA splicing E) requires RAG recombinase activity

E

TCR co-receptor on cytotoxic T cells that interacts with MHC II A) CD28 B) CD3 C) Fc (CD16) D) CD4 E) CD8

E

The T-cell receptor antigen recognition signal is transduced by A) TCR alpha chain B) TCR beta chain C) CD1 D) CD2 E) CD3

E

The first immunoglobulin heavy chain class to be expressed on the surface of a newly produced B-cell is A) IgA B) IgD C)IgE D)IgG E) IgM

E

Which class of antibody in the circulatory system of the fetus would be expected to play the greatest role in helping to protect the fetus from a virus that has infected the mom? A) IgA B) IgD C) IgE D) IgM E) IgG

E

T or F Antibody class switch recombination takes place in the bone marrow

F

T or F Antibody class switching from IgM to IgA occurs in the germinal center

F

T or F the membrane anchor of the BCR is contained in the light chain

F

(T or F) T cells expressing gamma-delta TCRs lack both CD4 and CD8 markers

T

T or F The TCR beta-chain locus contains many more D genes than does the BCR heavy chain locus

T

T or F the alpha chain of the TCR contains a C-terminal transmembrane anchor domain

T

T or F the potential diversity of the antigen binding site of the TCRs is much greater than that of the BCRs

T

T or F CD4+ T cells are precursors of Th1 and Th2 T lymphocytes

T

T or F ITAM motifs are phosphorylated by tyrosine kinases

T

T or F Production of antibodies by plasma cells require T-helper cells

T