CHAPTER 15

Select all of the statements that apply to a primary response to a T-dependent antigen:

- Takes 10-14 days to build a substantial amount of antibodies in the bloodstream. - Produces mainly IgM antibodies, but undergoes class switching to other classes near the end of the response. - Fine-tunes and increases strength of binding of antibody to antigen through the process of affinity maturation.

Please match the antibody type to the statement that accurately describes them to test your understanding of structure and functions of antibodies.

IgG - Most prevalent antibody in circulation IgA - Dimer that is a significant component of mucus and secretions IgM - Pentameric in circulation IgD - Involved in the development/maturation of immune response IgE - Mediates allergic responses

After repeated exposure to foreign material, innate immunity

continues to react the same way

Which of the following is the only antibody class capable of crossing the placenta?

IgG

Select all of the following that apply to a secondary response to a T-dependent antigen:

- May take only 2-4 days to build a substantial amount of antibodies in the bloodstream. - Produces mainly either IgG or IgA antibodies without shifting to other types. - Fine-tunes and increases strength of binding of antibody to antigen through the process of affinity maturation.

Please place the lymphocytes in the correct order in terms of clonal selection and expansion.

1 - Immature lymphocytes: antigen-receptors on the cytoplasmic membrane are not yet fully developed. 2 - Naive lymphocytes: antigen receptors are present but the cell has not encountered an antigen. 3 - Activated lymphocytes: antigen is bound to the receptor and the cell has received signals to proliferate. 4 - Effector lymphocytes: the activated lymphocytes produce effector cytokines in response to the specific antigen. 5 - Memory lymphocytes: long-lived descendents of the activated lymphocytes that are quickly reactivated in the presence of the same antigen.

Consider the figure below. Which part accounts for antigen-binding specificity?

A

Please select the INCORRECT statement regarding the outcomes of antigen-antibody binding.

ADCC - antibodies bind to a helminth and a neutrophil then engulfs the antibody-coated helminth.

Antigen-presenting cells

All of the answer choices are correct

If your humoral immune response were compromised, which of the following would happen?

Antibody production would decrease.

Antibodies are made by

B cells/plasma cells.

There are no antigens that can stimulate B cells without T cell help

FALSE

Match each of the antibody classes with its description.

IgM - First class produced in primary response. Forms a pentamer. Helps activate complement through the classical pathway. IgG - Main class found in blood. Only class that can cross the placenta. Found as a monomer. IgA - Most abundant class overall, but mainly found in mucosal secretions. Generally found as a dimer. IgE - Binds via Fc region to mast cells/basophils. Involved in allergic responses and responses to parasites. IgD - Involved in maturation of B lymphocytes and antibody responses, but function is largely uncharacterized.

When activated by antigen-presenting cells, helper T cells release what cytokine that activates B cells and cytotoxic T cells?

Interleukin-2

______ with antigen fragments displayed on their surfaces are known as antigen-presenting cells (APCs).

Macrophages

Please match the statements to the terms they describe to test your understanding of the possible end results of antibody binding antigen.

Opsonization - Coating of microbe with antibody to enhance phagocytosis Neutralization - Antibodies fill the surface receptors on microbe to prevent attachment to the host Complement system activation - Immune complexes activate complement proteins, leading to inflammation and production of MACs Immobilization and prevention of adherence - Antibodies bind to flagella preventing movement or to pili preventing attachment of bacteria Cross-linking - Formation of large Ab-Ag complexes as a result of the Ab binding two separate antigens Antibody-dependent cellular cytotoxicity (ADCC) - IgG molecules attach to a cell targeting it for attack by a NK cell

Cytotoxic T cells primarily are responsible for

cell-mediated immunity.

T-dependent antigens

characteristically have a protein component

If your cell-mediated immune response were compromised, which of the following would happen?

You would be more susceptible to viral infections

Antigens

are molecules that can be recognized by B or T cells

T cells

are responsible for cell-mediated immunity

Helper T cells

function in both cell-mediated and humoral immunity

A term synonymous with antibody is

immunoglobulin.

The adaptive immune response

involves memory of antigens from previous exposure

IgM is particularly effective in cross-linking antigens because

it is a pentamer.

The immune system responds more quickly to second exposure to an antigen because

memory B cells are produced during the first response

You are infected with an enveloped single-stranded RNA virus. Your immune system recognizes the antigen and responds. Plasma cells generate antibodies that bind to the virus, preventing it from entering your cells. This is an example of

neutralization.

B cells differentiate into ______, which make antibodies.

plasma cells

The antibody-producing progeny of an activated B cell are called ______.

plasma cells

All of the following cells have class II MHC receptors on their surface EXCEPT

red blood cells

Cytotoxic T cells know that a cell is infected because

that cell has antigens from the disease-causing microbe on its surface