Chap. 11 Immuno Exam 3

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.) -The antibody produced is of higher affinity in a secondary immune response. -The frequency of antigen-specific B cells is lower in a secondary immune response. -The level of somatic hypermutation is higher in a secondary immune response. -Higher levels of IgM are produced in secondary immune responses. -B cells do not require T-cell help in secondary immune responses. -Memory B cells express higher levels of MHC class II molecules. -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. -Memory B cells express higher levels of MHC class II molecules.

Which of the following characterizes immunological memory? (Select all that apply.) -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. -Naive T cells are activated more quickly when exposed to pathogen. -Memory B cells produce higher-affinity antibody than naive B cells. -Memory T cells undergo somatic hypermutation. -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.

Memory B cells differ from memory T cells in the following ways. (Select all that apply.) -They suppress naive antigen-specific lymphocytes during secondary immune responses. -They recirculate only through secondary lymphoid organs. -They secrete their antigen receptors throughout their life-span. -They generate long-lived clones of memory cells during the primary immune response.

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

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

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

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

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

_____ accounts for the production of different isoforms of the CD45 protein observed in naive, effector, and memory T cells. Isotype switching Affinity maturation Alternative splicing Somatic hypermutation Recirculation to peripheral tissues.

Alternative splicing

The CD45RA isoform is associated with stronger signals in response to antigen. TRUE FALSE

FALSE

Which of the following statements is incorrect regarding memory B cells? Memory B cells are maintained for life. In secondary responses, the number of pathogen-specific B cells is about 10-100-fold that seen in primary responses. The sensitivity of memory B cells is improved compared with naive B bells because affinity maturation has occurred. Memory B cells express lower levels of MHC class II and B7 than do naive B cells. 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? Naive pathogen-specific B cells are suppressed by negative signaling through FcγRIIB1. Naive pathogen-specific B cells isotype switch and hypermutate much more quickly during secondary immune responses. Memory B cells outnumber naive B cells. 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.

"Original antigenic sin" is best described as a phenomenon in which _____. a highly mutable virus gradually escapes from immunological memory and interferes with compensatory immune responses. latent viruses periodically activate effector T cells specific for the original antigen recognized in the primary immune response. the persistence of antigen is necessary to sustain maintenance of immunological memory. 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.

What would be 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 immune response using FcγRIIB1, and simultaneously bind to the same pathogen using its B-cell receptor? a positive signal leading to the production of low-affinity IgM antibodies a positive signal leading to isotype switching and the production of IgG, IgA, or IgE antibodies a positive signal leading to somatic hypermutation and the production of high-affinity IgM antibodies a negative signal leading to inhibition of the production of low-affinity IgM antibodies a negative signal leading to apoptosis.

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

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

exons A, B, and C; post-transcriptional

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

of affinity maturation.

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

the B cell becomes anergic