Chapter 16: The Immune System: Adaptive Immunity

The cell indicated on this illustration has the surface molecule

CD8

Why does B-cell proliferation and differentiation often require assistance from helper T cells?

Capping does not occur unless epitopes are found in multiple copies.

The molecule indicated on this illustration of the first signal during the activation of a cytotoxic T cell (TC) must be

Class I MHC

What is the function of class II MHC molecules?

Class II MHC is used to present extracellular antigen to CD4 cells.

A newborn receives passive immunity through

IgG

When comparing the primary and secondary immune responses, which of the following is true?

IgG titer levels are much higher during a secondary immune response.

This figure shows the structure of an ________ antibody.

IgM

Which two antibody classes are displayed on the surface of naïve B cells?

IgM and IgD

Which of the following accurately describes how a foreign molecule leads to the production of antibody?

Individual epitopes on an antigen are recognized and a single antibody is produced for each epitope.

The second signal required for TC activation is

secretion of the cytokine IL-2 from a TH1 cell.

IgG, IgA, IgM, IgD, and IgE are all examples of

Isotypes

Which of the following statements accurately describes how memory B cells become activated during the secondary immune response?

Memory B cells respond to soluble IL-4 and IL-6 without direct contact with TH cells

How are memory B cells able to persist for many years?

Memory B cells with receptors that match with antigen produce anti-apoptosis protein.

One health risk associated with excessive cytokine release is the chance of

severe tissue damage

The figure shown illustrates clonal expansion of activated B cells. What are the two cell types produced by this cell line?

Plasma cells and memory B cells

Clonal expansion of B cells occurs when a(n)

single B cell becomes activated when its receptor binds to a single epitope.

Which of the following statements correctly describes the molecules that elicit an immune response?

Small segments of an antigen that elicit an immune response are called epitopes.

MHC molecules are required for

T cell activation

A microbe is ingested and broken into fragments by an antigen-presenting cell (APC). Which of the following would you expect to occur?

T cells will bind to antigens on the surface of the APC

T cells that secrete IL-4, IL-5, and IL-6 and that play a major role in helping B cells are known as ________ cells.

TH2

Antigen bound by the molecule shown would be recognized by ________ cells.

Tc

T cells capable of killing virus-infected and cancer cells are known as ________ cells.

Tc

What step would have preceded the figure shown?

The T cell would have recognized antigen bound to an antigen-presenting cell.

How would you expect an injection of killed or attenuated Salmonella typhi, the causative agent of typhoid fever, to protect an individual

The injection would provide antigens recognizable by the immune system and memory cells would form to prevent typhoid fever in the future.

Which of the following would you expect to elicit the largest production of antibodies?

a complex protein with many different epitopes

Nathan was a ten-month-old male who had suffered much in his short life. Since birth he had experienced recurrent serious extracellular bacterial infections, all of which were resolved by antibiotic treatment. On Christmas Day, Nathan's mother discovered he had another high fever and a nonproductive cough (no mucus). He was also having trouble breathing. Fearing one more serious infection, Nathan's mother rushed him to the hospital. An X-ray showed the lung infiltrate with the appearance of ground glass. A tube was placed through Nathan's nose and into his lung, and a solution was used to wash out deep-lung contents for microscopic examination (bronchoalveolar lavage). The fluid yielded microscopic organisms. Nathan was hospitalized with pneumonia caused by Pneumocystis jirovecii, a yeastlike fungus. Although most of us have been infected with this organism, our immune systems almost always prevent disease. Finding the disease in Nathan suggested a serious immune dysfunction. An immunological workup revealed mild neutropenia (lower than normal numbers of neutrophils) but normal numbers of T and B cells, normal levels of complement, and normal complement activity. However, Nathan's blood exhibited exceptionally high levels of IgM but very low IgG and IgA levels. The physician suspected a specific defect in Nathan's T cells.

a mutation affecting CD40

Which of the following would most directly eliminate an intracellular pathogen such as a virus?

activation of cytotoxic T cells

If you had a box of 200 beads that were different shapes and you randomly chose and linked together 3 beads, you would be performing a process analogous to the way

antibody diversity is created within our bodies

The process illustrated in this figure is best described as

capping

The antigen-binding site on an antibody

contains highly variable amino acid sequences.

Which of the following cell types is considered a "nonprofessional" antigen-presenting cell?

fibroblast

The immunoglobulin superfamily of proteins includes

immunoglobulins, major histocompatibility complex, and B- and T-cell receptors.

The direct consequence of a CD40 protein on a B cell binding to a CD40 ligand on a T cell is

initiation of an intracellular signal required for B cell activation.

The figure shown illustrates a bacterial cell that

is broken down into many antigens.

Which of the following scenarios is an example of an allotypic difference?

A single amino acid change gives rise to a new form of IgG antibody in humans.

Which of the following statements is an example of a situation in which cross-protection will occur?

A vaccine is administered for one of two viruses that share epitopes.

Almost 95% of T cells entering the thymus die when apoptosis is triggered during

negative selection

What is the function of an antigen-presenting cell (APC)?

An APC presents antigen to helper T cells to activate the T cells during a cellular response.

T-cell receptors (TCRs) are only able to bind

peptides

Why are cytotoxic T (TC) cells more effective than antibodies at clearing viral infections?

Antibodies are only able to bind to extracellular antigen, and viruses tend to be intracellular.

Individuals with bare lymphocyte syndrome lack MHC II proteins. Which of the following could still occur in an individual lacking MHC II proteins?

B cells could produce IgM antibodies

Class switching is the process in which

B cells switch from producing IgM of IgD to producing IgE, IgG, or IgA.