Immunology Chapter 11

--- accounts for the production of different isoforms of the CD45 proteins observed in naive, effector and memory T cells. a. Isotype switching b. Affinity maturation c. Alternative splicing d. Somatic hypermutation e. Recirculation to peripheral tissues.

Alternative splicing

Naive T cells do not express _____. (Select all that apply.) a. CD25 b. CD45RA c. CCR7 d. IFN-γ e. FasL.

CD25 , IFN-γ, and FasL.

which of the following molecules is not elevated on the surface of memory B cells compared with naive B cells? a. MHC class II molecules b. CD45RA c. antigen receptor d. CD27 e. co-stimulatory molecules.

CD45RA

Which of the following explain why infections with influenza virus erode immunological memory over time? (Select all that apply.) a. Influenza is a highly mutable virus that changes its epitope composition. b. A compensatory immune response to new epitope variants is suppressed in naive B cells. c. The antibody response is directed only toward new epitope variants, resulting in a decreased memory response. d. Cross-linking of B-cell receptor and FcγRIIB1 on memory B cells induces anergy. e. Naive B cells are suppressed by cytokines made by memory B cells.

Influenza is a highly mutable virus that changes its epitope composition and A compensatory immune response to new epitope variants is suppressed in naive B cells.

which of the following statements is incorrect regarding memory B cells? a. Memory B cells are maintained for life. b. In secondary responses, the number of pathogen-specific B cells is about 10-100-fold that seen in primary responses. c. The sensitivity of memory B cells is improved compared with naive B bells because affinity maturation has occurred. d. Memory B cells express lower levels of MHC class II and B7 than do naive B cells. e. Memory B cells differentiate into plasma cells more rapidly than do naive B cells.

Memory B cells express lower levels of MHC class II and B7 than do naive B cells.

During a secondary immune response, high affinity IgG antibodies are produced. Which of the following best explains why low affinity IgM antibodies are not made? a. Naive pathogen-specific B cells are suppressed by negative signaling through FcγRIIB1. b. Naive pathogen-specific B cells isotype switch and hypermutate much more quickly during secondary immune responses. c. Memory B cells outnumber naive B cells. d. Low-affinity IgM antibodies are made only when antigen concentration is exceedingly high.

Naive pathogen-specific B cells are suppressed by negative signaling through FcγRIIB1.

which of the following explains why the first baby born to a RHD- mother and a RhD+ father does not develop hemolytic disease of the newborn? a. Fetal erythrocytes do not cross the placenta and therefore do not stimulate an antibody response. b. The antibodies made by the RhD- mother during the first pregnancy are predominantly IgM and have low affinity for the Rhesus antigen. c. Maternal macrophages in the placenta bind to anti-Rhesus antibodies and prevent their transfer to the fetus. d. Hemolytic disease of the newborn is a T-cell-mediated disease and maternal T cells do not cross the placenta during pregnancy. e. The Rhesus antigen is not immunogenic and does not stimulate an antibody response.

The antibodies made by the RhD- mother during the first pregnancy are predominantly IgM and have low affinity for the Rhesus antigen.

which of the following characterizes immunological memory? a. The host retains the capacity to mount a secondary immune response. b. The host retains the ability to respond to pathogen many years after primary exposure. c. Naive T cells are activated more quickly when exposed to pathogen. d. Memory B cells produce higher-affinity antibody than naive B cells. e. Memory T cells undergo somatic hypermutation. f. Memory T cells express CD45RA.

The host retains the capacity to mount a secondary immune response, The host retains the ability to respond to pathogen many years after primary exposure, Memory B cells produce higher-affinity antibody than naive B cells.

imagine a situation in which an individual who has a latent cytomegalovirus (CMV) infection recieves a hemtopoietic stem-cell transplant. Which of the following would likely occur? a. The memory T cells present at the time of transplantation would inhibit activation of newly generated naive T cells. b. The CMV viral load would increase exponentially, overcoming the host and causing death. c. The transplant-derived naive T cells would be activated and give rise to memory T cells that would persist and control viral load. d. There would be a rapid increase in CMV viral load and expansion of T cells bearing CD45RA.

The transplant-derived naive T cells would be activated and give rise to memory T cells that would persist and control viral load.

Memory B cell differ from memory T cells in the following ways. a. They suppress naive antigen-specific lymphocytes during secondary immune responses. b. They recirculate only through secondary lymphoid organs. c. They secrete their antigen receptors throughout their life-span. d. They generate long-lived clones of memory cells during the primary immune response.

They suppress naive antigen-specific lymphocytes during secondary immune responses and They recirculate only through secondary lymphoid organs.

Original antigenic sin is best described as a phenomenon in which a. a highly mutable virus gradually escapes from immunological memory and interferes with compensatory immune responses. b. latent viruses periodically activate effector T cells specific for the original antigen recognized in the primary immune response. c. the persistence of antigen is necessary to sustain maintenance of immunological memory. d. memory T cells no longer express the same profile of adhesion molecules and cytokine receptors compared with the original profile of the naive precursor T cell.

a highly mutable virus gradually escapes from immunological memory and interferes with compensatory immune responses.

by which process are fetal erythrocytes destroyed in hemolytic anemia of the newborn? a. lysis of erythrocytes by cytotoxic T cells b. lysis of erythrocytes by complement activation c. clearance of antibody-coated erythrocytes by macrophages in the fetal spleen d. lysis of erythrocytes by NK cells via antibody-dependent cell-mediated cytotoxicity e. cytotoxicity caused by major basic protein released from eosinophils.

clearance of antibody-coated erythrocytes by macrophages in the fetal spleen

unlike naive lymphocytes, memory lymphocytes a. do not recirculate between the blood and secondary lymphoid organs b. do not require the receipt of survival signals through their antigen receptors in order to persist c. are immortal and continue to divide throughout the lifetime of an individual d. secrete antibody continuously, although at a much lower rate than plasma cells e. do not express CD27.

do not require the receipt of survival signals through their antigen receptors in order to persist

Which of the following are not a component for immunological memory? a. effector B cells b. memory T cells c. memory B cells d. long-lived plasma cells.

effector B cells

The production of CD45RO results from the removal of _____ during _____ processing. a. domain A; post-translational b. domain A; post-transcriptional c. exons A, B, and C; post-translational d. exons A, B, and C; post-transcriptional e. exon A; post-transcriptional.

exons A, B, and C; post-transcriptional

Effector memory cells enter _____, whereas central memory cells enter _____. a. B-cell follicles; T-cell zones of secondary lymphoid tissues b. T-cell zones of secondary lymphoid tissues; B-cell follicles c. secondary lymphoid tissues; primary lymphoid tissues d. T-cell zones of secondary lymphoid tissues; inflamed tissues e. inflamed tissues; T-cell zones of secondary lymphoid tissues.

inflamed tissues; T-cell zones of secondary lymphoid tissues.

RhoGAM is administered to pregnant RhD- women so as to a. stimulate only anti-RhD IgM antibody b. cause selective removal of anti-RhD memory B cells from the maternal circulation c. inhibit a primary immune response to RhD antigen d. block transcytosis of IgG to fetal circulation by interfering with FcRn function e. prevent hemolytic anemia of the newborn

inhibit a primary immune response to RhD antigen and prevent hemolytic anemia of the newborn

what would the outcome if a naive B cell were to bind to pathogen coated with specific antibody made by an effector B cell in a primary response using FcγRIIB1, and simultaneously bind to the same pathogen using its B-cell receptor? a. a positive signal leading to the production of low-affinity IgM antibodies b. a positive signal leading to isotype switching and the production of IgG, IgA, or IgE antibodies c. a positive signal leading to somatic hypermutation and the production of high-affinity IgM antibodies d. a negative signal leading to inhibition of the production of low-affinity IgM antibodies e. a negative signal leading to apoptosis.

negative signal leading to inhibition of the production of low-affinity IgM antibodies

the efficiency & specificity of adaptive immune defenses and immunological memory improve each time a particular pathogen is encountered because a. of protective immunity b. effector memory T cells outnumber central memory T cells c. the half-life of antibodies made in secondary and tertiary immune responses exceeds that of antibodies made in primary immune responses. d. of affinity maturation.

of affinity maturation.

all of the following are ways in which plasma cells differ from memory cells except a. plasma cells lack surface immunoglobulin b. cellular morphology c. plasma cells are CD27-negative d. plasma cells have undergone isotype switching e. plasma cells are short-lived.

plasma cells have undergone isotype switching

When a naive B cells binds to an IgG:antigen complex in its cell surface using FcγRIIB1, while simultaneously binding to the same antigen using membrane-bound IgM, _____. a. the IgG:antigen complex is endocytosed b. the B cell becomes anergic c. the B cell will switch isotype to IgG d. the B cell undergoes affinity maturation 168 e. the B cell secretes large amounts of IgM before becoming a memory B cell.

the B cell becomes anergic

In which ways do memory B cells active in a secondary immune response differ from the naive B-cell population activated in a primary immune response? (Select all that apply.) a. The antibody produced is of higher affinity in a secondary immune response. b. The frequency of antigen-specific B cells is lower in a secondary immune response. c. The level of somatic hypermutation is higher in a secondary immune response. d. Higher levels of IgM are produced in secondary immune responses. e. B cells do not require T-cell help in secondary immune responses. f. Memory B cells express higher levels of MHC class II molecules. g. Naive B cells express higher levels of co-stimulatory molecules.

the antibody produced is of higher affinity in a secondary immune response, The level of somatic hypermutation is higher in a secondary immune response, and Memory B cells express higher levels of MHC class II molecules.