5. Secondary lymphoid organs
A. are strategically located in the body.
B. facilitate interactions between cells.
C. are hematopoietic.
D. are the site of T cell maturation.
E. are strategically located in the body AND facilitate interactions between cells.

E. are strategically located in the body AND facilitate interactions between cells.

6. Epitopes or antigenic determinants
A. are parts of the antibody molecule.
B. are T cell receptors.
C. are a portion of antigen recognized by antibody.
D. may be approximately 10-25 amino acids in length.
E. are a portion of antigen recognized by antibody AND may be approximately 10-25 amino acids in length.

E. are a portion of antigen recognized by antibody AND may be approximately 10-25 amino acids in length.

The humoral immune response is delivered by

A. antibodies.
B. T cells.
C. lymphokines.
D. antigens.

A. antibodies.

Which of the following is not typical of an antigen?
A. Low molecular weight

B.

Protein

C.

Foreign

D.

Polysaccharide

E.

Low molecular weight AND protein

A. Low molecular weight

Specific regions on an antigen molecule to which the immune response is directed are

A. antigenic determinants.
B. an autoimmune response.
C. monomers.
D. allergens.

A. antigenic determinants.

Which of the following molecules would be expected to be immunogenic?

A. Progesterone, a lipid hormone.

B. Serum albumin, a large protein.

C. Glucose, a simple sugar.

D. Linoleic acid, a fatty acid.

B. Serum albumin, a large protein.

Which of the following is/are secondary lymphoid organ(s)?
A. Thymus

B. Spleen

C. Lymph nodes

D. Bone marrow

E. Spleen AND lymph nodes

E. Spleen AND lymph nodes

A term synonymous with antibody is
A. antigen.
B. epitope.
C. determinant.
D. immunoglobulin.

D. immunoglobulin.

Which of the following do not induce a strong immune response?
A. Lipids

B. Proteins

C. Polysaccharides

D. Simple sugars.

E. Lipids AND simple sugars

E. Lipids AND simple sugars

14. There are ______ classes of antibody.
A. one

B. three

C. five

D. seven

C. five

Which of the following antibodies is a pentamer?
A. IgA
B. IgD
C. IgM
D. IgE

C. IgM

. The chains of an antibody molecule are bonded to one another by
A. disulfide bonds.
B. hydrogen bonds.
C. ionic bonds.
D. oxygen bonds.

A. disulfide bonds.

Which of the following antibodies is a dimer?
A. IgA
B. IgD
C. IgM
D. IgE

A. IgA

The immunoglobulin monomer consists of
A. four large chains.

B. two heavy and two light chains.

C. five light chains.

D. three heavy and three light chains.

B. two heavy and two light chains.

Which class of antibody accounts for the bulk of the circulating antibody?
A. IgA
B. IgD
C. IgG
D. IgE

C. IgG

The characteristic function and properties of each class of antibody is determined by the
A. variable region on the light chain.
B. epitope.
C. constant region on the light chain.
D. constant region on the heavy chain.
E. variable region on the heavy chain.

D. constant region on the heavy chain.

An IgG molecule has two
A. heavy chains.
B. light chains.
C. antibody binding sites.
D. antigen binding sites.
E. heavy chains, light chains AND antigen binding sites.

E. heavy chains, light chains AND antigen binding sites.

The variable region of an antibody occurs
A. only on the heavy chains.
B. only on the light chains.
C. on one of the light chains.
D. on all four chains.

D. on all four chains.

Each class of antibody is specifically defined by its
A. amino acid sequence of the constant region of the heavy chain.
B. amino acid sequence of the variable region of the light chain.
C. ability to cross the placenta.
D. disulfide bonds.

A. amino acid sequence of the constant region of the heavy chain.

Antigens interact with antibodies at
A. the outer end of each arm of the Y.
B. the junction of heavy and light chains.
C. different regions depending on the class of antibody.
D. the bottom stem of the heavy chain of the Y.

A. the outer end of each arm of the Y.

Ag-Ab binding may result in
A. neutralization.
B. immobilization.
C. agglutination.
D. opsonization.
E. All of the choices are correct.

E. All of the choices are correct.

The Fc region on IgG
A. interacts with complement.
B. attaches to receptors on macrophages.

C. reacts with and coats the antigen.
D. contains a variable region.
E. interacts with complement AND attaches to receptors on macrophages.

E. interacts with complement AND attaches to receptors on macrophages.

How long after initiation of a primary response do significant amounts of antibody appear in the blood?
A. One day

B. 10-14 days
C. 4 weeks
D. 6 months

B. 10-14 days

The only class of antibody that can cross the placenta is
A. IgA.
B. IgD.
C. IgG.
D. IgE.

C. IgG.

Which is the first antibody class made during the primary response to an antigen?
A. IgA
B. IgM
C. IgG
D. IgE

B. IgM

Which of the following is the most abundant immunological class produced?
A. IgA
B. IgD
C. IgG
D. IgE

A. IgA

Which is the most efficient at initiating the classical pathway of the complement cascade?
A. IgA
B. IgD
C. IgM
D. IgE

C. IgM

Which of the following class of antibody is primarily found in external secretions?
A. IgA
B. IgD
C. IgG
D. IgE

A. IgA

The function of the secretory component of the IgA molecule is
A. to protect IgA from being destroyed by proteolytic enzymes.
B. to coat the antigen.
C. opsonization.
D. to fix IgA to the antigen.

A. to protect IgA from being destroyed by proteolytic enzymes.

The immunoglobulin that is important in hypersensitivity reactions is
A. IgA.
B. IgD.
C. IgG.
D. IgE.

D. IgE.

35. According to the clonal selection theory
A. antibodies are modified, at the time of antigen exposure, to specifically react with the antigen.
B. self-reactive T cells are killed in the thymus.
C. B cells producing autoantibodies are eliminated in the thymus.
D. each B cell is already programmed to produce a specific antibody.
E. self-reactive T cells are killed in the thymus AND B cells producing autoantibodies are eliminated in the thymus.

D. each B cell is already programmed to produce a specific antibody.

"Clonal selection" and "clonal expansion"
A. implies that each individual lymphocyte produces a single antibody.
B. describes how a single lymphocyte proliferates in a population of effector cells.

C. depends on an antibody recognizing a specific epitope.
D. explain how an antigen stimulates the production of matching antibodies.

E. All of the above

E. All of the above

T cells and B cells are produced in the

A. bone marrow.
B. thymus.
C. Peyer's patches.
D. nervous tissue.

A. bone marrow.

T cells mature in the
A. bone marrow.
B. thymus.
C. Peyer's patches.
D. nervous tissue.

B. thymus.

The cells that actually secrete antibodies are
A. plasma cells.
B. natural killer cells.
C. phagocytes.
D. T cells.

A. plasma cells.

CD4 cells are also known as ...

A. T helper cells.
B. natural killer cells.

C. T cytotoxic cells.
D. macrophages.

E. neutrophils.

A. T helper cells.

CD8 cells are

A. T helper cells.

B. natural killer cells.

C. T cytotoxic cells.
D. macrophages.

C. T cytotoxic cells.

Antigens may be processed for presentation by
A. macrophages.
B. dendritic cells.
C. erythrocytes.
D. T cytotoxic cells.
E. macrophages AND dendritic cells.

E. macrophages AND dendritic cells.

43. Macrophages and dendritic cells are
A. T cells.
B. B cells.
C. antigen-presenting cells.
D. antibody-producing cells.

C. antigen-presenting cells.

Only antigen-presenting cells
A. produce antibodies.
B. activate cytotoxic T cells.
C. produce MHC class I molecules.
D. produce MHC class II molecules.

D. produce MHC class II molecules.

It would be useful if antigens were delivered directly to
A. Peyer's patches.
B. W Cells.
C. M cells.
D. red blood cells.
E. Peyer's patches AND M cells.

E. Peyer's patches AND M cells.

46. Class II MHC molecules are found primarily on
A. macrophages.
B. dendritic cells.
C. erythrocytes.
D. T cytotoxic cells.
E. macrophages AND dendritic cells.

E. macrophages AND dendritic cells.

The stimulation of B cells to divide and mature is provided by
A. T helper cells.
B. macrophages.
C. T cytotoxic cells.
D. plasma cells.

A. T helper cells.

The peptides presented by MHC class II peptide molecules are
A. from plasma cells.
B. exogenous antigens.
C. endogenous antigens.
D. from T helper cells.

B. exogenous antigens.

T-independent antigens
A. include polysaccharides.
B. require the involvement of T cells.
C. interact with MHCI molecules.
D. are usually proteins.
E. include polysaccharides AND are usually proteins.

A. include polysaccharides.

Memory cells may take the form of
A. B cells.
B. T cytotoxic cells.
C. T helper cells.
D. All of the choices are correct.

D. All of the choices are correct.

The surface receptors on B and T cells both
A. play the same role in each type of cell.
B. bind to free antigen.
C. have two binding sites for antigen.
D. have variable and constant regions.
E. play the same role in each type of cell AND have two binding sites for antigen.

D. have variable and constant regions.

Which is involved in reacting to virus-infected cells?
A. Cell-mediated immunity

B. T cytotoxic cells
C. B cells
D. MHC I
E. Cell-mediated immunity, T cytotoxic cells, AND MHC I

E. Cell-mediated immunity, T cytotoxic cells, AND MHC I

Perforin is produced by
A. B cells.
B. macrophages.
C. NK cells.
D. T helper cells.
E. macrophages AND NK cells.

C. NK cells.

Giant cells are
A. a fusion of B cells.
B. a fusion of T cells.
C. used to contain bacterial infections.
D. activated T helper cells.
E. a fusion of T cells AND used to contain bacterial infections.

C. used to contain bacterial infections.

Apoptosis
A. is a form of cell suicide.
B. is induced in target cells by effector T cytotoxic cells.
C. results in T cell death.
D. refers to the transformation of B cells into plasma cells.
E. is a form of cell suicide AND is induced in target cells by effector T cytotoxic cells.

E. is a form of cell suicide AND is induced in target cells by effector T cytotoxic cells.

How is the central portion of a T cell receptor complex functionally analogous to the center of the B cell receptor complex?

A. It has two pieces (chains), just like a B-cell receptor.

B. Both receptors bind epitopes (small amino acid sections of antigen molecules).
C. Both bind structures directly on the surface of microbes.
D. Both can be secreted from lymphocytes to bind to pathogens under certain situations.

B. Both receptors bind epitopes (small amino acid sections of antigen molecules).

How is a T-cell receptor different from a B-cell receptor?
A. T-cell receptors must have antigen broken down inside a cell and presented to them by a Major Histocompatibility Complex (MHC) molecule.
B. B-cell receptors must have antigen broken down inside a cell and presented to them by a Major Histocompatibility Complex (MHC) molecule.
C. T-cell receptors are composed of 4 protein chains (pieces), while B-cell receptors are composed of only 2 pieces.
D. T-cell receptors are eventually secreted into the bloodstream by activated T-cells, whereas B-cell receptors are not; they always stay with the B-cell.

A. T-cell receptors must have antigen broken down inside a cell and presented to them by a Major Histocompatibility Complex (MHC) molecule.

Why would a person who has their tonsils removed be more susceptible to certain types of infections of the throat and respiratory tract?
A. Tonsils produce high levels of lactoferrin, a strong natural antibacterial compound.
B. Tonsils produce large amounts of interferons, natural antiviral compounds.
C. Tonsils are secondary lymphoid organs-they help to provide a constant response to the microbes in the oral cavity, helping to keep them in check and preventing them from spreading to other areas.
D. Tonsils are the location where T cells develop and mature. Without them, a person won't have T cells, and will be more likely to suffer from infections that would normally be eliminated by such cells.

C. Tonsils are secondary lymphoid organs-they help to provide a constant response to the microbes in the oral cavity, helping to keep them in check and preventing them from spreading to other areas.

Would a denatured antigen be expected to have the same epitopes as its native (non-denatured) counterpart? Why?
A. Yes-epitopes are just a sequence of amino acids in a row, so they do not change regardless of 3D shape of the protein molecule they lie within.
B. No-ALL epitopes are dependent on being in the proper original 3D conformation in the protein they arise within. Denaturing them would destroy them by destroying that conformation.
C. Yes AND No-SOME epitopes are dependent on 3D conformation (conformational epitopes), while some simply depend on the sequence of amino acids (linear epitopes). So, really, it depends on the particular epitope.

C. Yes AND No-SOME epitopes are dependent on 3D conformation (conformational epitopes), while some simply depend on the sequence of amino acids (linear epitopes). So, really, it depends on the particular epitope.

In opsonization with IgG, why would it be important that IgG react with the antigen BEFORE a phagocytic cell recognizes the antibody molecule?
A. If the IgG is bound to the phagocyte BEFORE opsonization, it would most likely be ingested by the phagocyte before it could bind to a pathogen (it would be "naked," so to speak).

B. Binding of IgG by phagocytes would block the antigen binding sites on the IgG molecules, preventing them from binding to the microbes.
C. Binding of IgG by phagocytes changes their conformation-and by changing their protein conformation, their antigen binding sites are changed and they can no longer recognize their specific antigenic epitopes.
D. Binding of antibody by phagocytes results in immediate release of protein-destroying enzymes to the outside of the cell. Since antibodies are proteins, they would be destroyed by these enzymes (and would then be unable to bind to their specific antigenic epitopes).

A. If the IgG is bound to the phagocyte BEFORE opsonization, it would most likely be ingested by the phagocyte before it could bind to a pathogen (it would be "naked," so to speak).

A scientist reports the isolation of a new blood-borne virus that completely shuts down presentation of viral epitopes on MHC molecules in the cells it infects. He produces an internet video describing it and how it will be indestructible by CD8+ cytotoxic T cells and will kill millions (if not billions) of people.The medical community quickly denounces the dire warning as irrevlevant, and the whole thing is quickly forgotten-why?

A. CD8+ T cells are not the cells that are responsible for killing virally infected cells. The terrorist mad scientist is a misinformed idiot.

B. While CD8+ T cells ARE important for eliminating a viral infection, they are not the ONLY things that are capable of doing so. Natural killer cells can kill virally infected cells that have shut down MHC antigen presentation, and interferons can assist in cleaning virally infected cells.

C. A blood-borne virus would not be capable of rapidly infecting millions of people, due to its difficult mode of transmission.

D. B cells would be primed right away to produce complement proteins to destroy the virus. This would prevent cells from being infected with it in the first place. His plot would be foiled.

E. While CD8+ T cells ARE important for eliminating a viral infection, they are not the ONLY things that are capable of doing so. Natural killer cells can kill virally infected cells that have shut down MHC antigen presentation, and interferons can assist in cleaning virally infected cells AND a blood-borne virus would not be capable of rapidly infecting millions of people, due to its difficult mode of transmission.

E. While CD8+ T cells ARE important for eliminating a viral infection, they are not the ONLY things that are capable of doing so. Natural killer cells can kill virally infected cells that have shut down MHC antigen presentation, and interferons can assist in cleaning virally infected cells AND a blood-borne virus would not be capable of rapidly infecting millions of people, due to its difficult mode of transmission.

The best possible analogy available below for the way in which variable (V), diversity (D), and joining (J) antibody gene segments get put together to create the diversity possible in hypervariable regions is
A. to think of the various segments as a deck of cards-when you get dealt a hand of five cards, you have a very high likelihood of getting a diferent hand every time. The quality of the hand you have dealt will dictate whether you have a "winning" hand (capable of binding to antigenic epitopes).

B. to think of the various segments as the pieces of a house-you need a strong foundation first (the joining segments), followed by a frame (the diversity segments), then the interior walls (the variable segments) before the structure is complete.
C. to think of the various segments as building a highway-you need to prepare the area first by clearing a path (the joining segments do this), then grade/slope the area (the diversity segments) before you can finally lay down the asphalt (the variable segments).
D. to think of the various segments as a bingo game-each segment is randomly selected, but you're going to need one of each V, D, and J to form a functional molecule. The "right" combination varaies depending on which antigen is eventually going to be binding to the molecule (i.e., your bingo card would be the eventual antigen, and the random calling out of the number/letter combinations would be the forming of the VDJ hypervariable region).

D. to think of the various segments as a bingo game-each segment is randomly selected, but you're going to need one of each V, D, and J to form a functional molecule. The "right" combination varaies depending on which antigen is eventually going to be binding to the molecule (i.e., your bingo card would be the eventual antigen, and the random calling out of the number/letter combinations would be the forming of the VDJ hypervariable region).