Immunology Exam 5

A vaccine containing an weakened pathogen is a(n) _____________ vaccine. attenuated adjuvant inactivated toxoid conjugated

attenuated

Which of the following statements regarding B cells is NOT true? Activation of B cells often requires cytokines. B cells often require T cell help to be activated by protein antigens. Activation of B cells requires class I MHC. B cells can act as antigen-presenting cells.

Activation of B cells requires class I MHC.

Which of the following statements is NOT true about antibodies? Antibodies protect against viruses by binding to them and perforating them. Antibodies protect against viruses by binding to them and presenting them to phagocytes. Antibodies are secreted by plasma cells. Antibodies protect against viruses by binding to them and neutralizing them. Antibodies activate complement.

Antibodies protect against viruses by binding to them and perforating them.

Which of the following is/are true of IgG? IgG I. crosses the placenta. II. is the largest immunoglobulin. III. is responsible for clearing parasitic infections. I only III only I and II II and III I, II, and III

I only

Which of the following would be best able to neutralize botulinum toxin secreted in the g.i. tract? IgE found in the serum IgG found in the serum IgA secreted in the mucosa IgA found in the serum Membrane-bound IgM

IgA secreted in the mucosa

__________ antibodies are responsible for allergic reactions. IgM IgG IgA IgD IgE

IgE

Which of the following would be produced by a response to T-independent Ags? long-lasting memory to the Ag IgA IgM memory B cells memory T cells

IgM

IL-4 induces a class switch from: IgM to IgA IgM to IgD IgM to IgE IgM to IgG

IgM to IgE

IFN- γ induces a class switch from: IgM to IgD IgM to IgE IgM to IgG IgM to IgA

IgM to IgG

All of the following are true about IgG EXCEPT: It is the immunoglobulin with the highest serum concentration in a secondary immune response. It is the most important antibody in mucosal immunity. It can activate complement. It has multiple subtypes. It is found in the serum of newborns.

It is the most important antibody in mucosal immunity.

The heavy chain class switch is regulated by: antigen presenting cells, such as macrophages T helper cytokines RAG-1 and RAG-2 diacylglycerol

T helper cytokines

Which of the following is true about complement? The alternative and classical pathways merge at C3. C1 activation begins the alternate pathway. The alternative pathway requires Ag-Ab complexes to get started. The MBL pathway begins with factor B (Bf) activation. C3a, C4a, and C5a make up the MAC.

The alternative and classical pathways merge at C3.

Assume the FcRs found on the cell, below, are FcγRIIIA receptors. If they are engaged by binding antibodies, which of the following will occur? antibody-dependent cellular cytotoxicity mast cell degranulation phagocytosis feedback inhibition

antibody-dependent cellular cytotoxicity

IgA can be secreted into the mucosa because it: can bind the poly-Ig receptor on epithelial cells. has a special amino acid sequence making it membrane-bound. is small enough to squeeze between epithelial cells. has special receptors that bind to adhesion molecules on epithelial cells. is synthesized on the luminal side of epithelial cells and thus secreted directly into the lumen.

can bind the poly-Ig receptor on epithelial cells.

Assume the FcRs found on the cell, below, are FcγRIIB receptors. If they are engaged by binding antibodies, which of the following will occur? mast cell degranulation phagocytosis feedback inhibition antibody-dependent cellular cytotoxicity

feedback inhibition

T-independent Ags do NOT: get presented by MHC class II. have repeating epitopes. activate B cells. bind BCRs. induce B cell proliferation.

get presented by MHC class II.

If an individual has antibodies in his serum against a particular pathogen, this means that he: has been exposed to that pathogen or its components. has recovered fully from infection by that pathogen. is immune to further infection by that pathogen. has an active infection by that pathogen.

has been exposed to that pathogen or its components.

Assume the FcRs found on the cell, below, are FcεRI receptors. If they are engaged by binding antibodies, which of the following will occur? antibody-dependent cellular cytotoxicity mast cell degranulation phagocytosis feedback inhibition

mast cell degranulation

To which of these cells does IgE bind to aid in expulsion of parasites from the body? B cells T cells mast cells macrophages neutrophils

mast cells

A bacterium has a capsule that prevents phagocytosis. Which of the following would be best able to respond successfully to this bacterium? an NK cell opsonizing Abs neutralizing Abs C3a, C4a, and C5a a cytotoxic T cell

opsonizing Abs

Assume the FcRs found on the cell, below, are FcγRI receptors. If they are engaged by binding antibodies, which of the following will occur? mast cell degranulation phagocytosis feedback inhibition antibody-dependent cellular cytotoxicity

phagocytosis

B cell isotype switching is important for: increasing the avidity of the antibody. signaling the B cells to become activated by follicular dendritic cells. signaling B cells to leave the lymph nodes and secrete antibody at the site of infection. providing antibodies of many different antigen specificities. providing antibodies which can perform different effector functions.

providing antibodies which can perform different effector functions.

Affinity maturation of the humoral immune response is due to: selection of T cells with the lowest helper potential. isotype switching. DNA recombination by products of the RAG genes. selection of B cells with the highest affinity for antigen. continued stimulation of B cells by high levels of antigen on the FDC.

selection of B cells with the highest affinity for antigen.

Germinal centers are: common in unimmunized mice. sites of rapid antigen-induced B cell division in the lymph nodes and spleen. None of these answers is true. surrounded by naïve T cells waiting to be activated. areas of lymphocyte generation in the bone marrow.

sites of rapid antigen-induced B cell division in the lymph nodes and spleen.

The process of ___________ is responsible for affinity maturation. germ-line diversity junctional diversity allelic exclusion combinatorial joining somatic hypermutation

somatic hypermutation