1. Which one of the following is an attribute of the innate, rather than the adaptive (acquired), arm of our host defenses?

(A) Is highly specific in its response to bacteria

(B) Responds to viruses and fungi, but not bacteria

(C) Exhibits memory following exposure to bacteria

(D) Is part of our host defense against bacteria but not against fungi

(E) Is as effective the first time it is exposed to bacteria as it is subsequent times

2. Regarding antibody-mediated immunity and cell-mediated immunity, which one of the following is the most accurate?

(A) Antibody-mediated immunity helps prevent graft rejection.

(B) Antibody-mediated immunity protects against anaphylactic shock.

(C) Antibody-mediated immunity protects against autoimmune diseases.

(D) Cell-mediated immunity neutralizes extracellular viruses.

(E) Cell-mediated immunity protects against fungal infections.

3. Which one of the following is most likely to induce an IgM antibody response without the participation of helper T cells?

(A) Diphtheria toxoid

(B) Pneumococcal capsular polysaccharide

(C) Pneumococcal polysaccharide conjugated to diphtheria toxoid

(D) Tetanus toxoid

(E) Toxic shock syndrome toxin

4. Regarding haptens, which one of the following is the most accurate?

(A) A hapten is the antigen-binding site in the hypervariable region of IgG.

(B) A hapten cannot induce antibody by itself but can do so when covalently bound to a carrier protein.

(C) A hapten can bind to the antigen receptor of CD4-positive T cells without being processed by macrophages.

(D) A hapten is defined by its ability to bind to the smaller of the two polypeptides that comprise the class I MHC proteins.

5. Certain components of our immune system are characterized by two attributes: being able (1) to respond specifically to microbes and (2) to exhibit memory of having responded to a particular microbe previously. Which one of the following has BOTH specificity and memory?

(A) B cells

(B) Basophils

(C) Dendritic cells

(D) Macrophages

(E) Neutrophils

6. Your patient says that she must travel on business 3 days from now to a country where hepatitis A is endemic. She just read in the newspaper that there are two types of protection against this disease: one is a vaccine that contains killed hepatitis A virus, and the other is serum globulin preparation that contains antibodies to the virus. She asks which you would recommend and for what reason?

(A) The vaccine containing killed hepatitis A virus is best because it induces the most antibody.

(B) The vaccine containing killed hepatitis A virus is best because it provides the most long-lived immunity.

(C) The serum globulin preparation containing antibodies against the virus is best because it provides immunity in the shortest time.

(D) The serum globulin preparation containing antibodies against the virus is best because it provides the most long-lived immunity.

7.Which category of hypersensitivity BEST describes hemolytic disease of the

newborn caused by Rh incompatibility?

(A) Atopic or anaphylactic

(B) Cytotoxic

(C) Immune complex

(D) Delayed

8. The principal difference between cytotoxic (type II) and immune complex (type III) hypersensitivity is:

(A) The class (isotype) of antibody

(B) Whether the antibody reacts with the antigen on the cell or reacts with antigen before it interacts with the cell

(C) The participation of complement

(D) The participation of T cells

9. A child stung by a bee experiences respiratory distress within minutes and lapses into unconsciousness. This reaction is probably mediated by:

(A) IgE antibody

(B) IgG antibody

(C) Sensitized T cells

(D) Complement

(E) IgM antibody

10. A patient with rheumatic fever develops a sore throat from which β-hemolytic streptococci are cultured. The patient is started on treatment with penicillin, and the sore throat resolves within several days. However, 7 days after initiation of penicillin therapy, the patient develops a fever of 103°F, a generalized rash, and proteinuria. This MOST probably resulted from:

(A) Recurrence of the rheumatic fever

(B) A different infectious disease

(C) An IgE response to penicillin

(D) An IgG-IgM response to penicillin

(E) A delayed hypersensitivity reaction to penicillin

11. A kidney biopsy specimen taken from a patient with acute glomerulonephritis and stained with fluorescein-conjugated anti-human IgG antibody would probably show:

(A) No fluorescence

(B) Uniform fluorescence of the glomerular basement membrane

(C) Patchy, irregular fluorescence of the glomerular basement membrane

(D) Fluorescent B cells

(E) Fluorescent macrophages

12. A patient with severe asthma gets no relief from antihistamines. The symptoms are MOST likely to be caused by:

(A) Interleukin-2

(B) Slow-reacting substance A (leukotrienes)

(C) Serotonin

(D) Bradykinin

13. Hypersensitivity to penicillin and hypersensitivity to poison oak are both:

(A) Mediated by IgE antibody

(B) Mediated by IgG and IgM antibody

(C) Initiated by haptens

(D) Initiated by Th-2 cells

14. A recipient of a two-haplotype MHC-matched kidney from a relative still needs immunosuppression to prevent graft rejection because:

(A) Graft-versus-host disease is a problem

(B) Class II MHC antigens will not be matched

(C) Minor histocompatibility antigens will not be matched

(D) Complement components will not be matched

15. Bone marrow transplantation in immunocompromised patients presents which major problem?

(A) Potentially lethal graft-versus-host disease

(B) High risk of T-cell leukemia

(C) Inability to use a live donor

(D) Delayed hypersensitivity

16. What is the role of class II MHC proteins on donor cells in graft rejection?

(A) They are the receptors for interleukin-2, which is produced by macrophages when they attack the donor cells.

(B) They are recognized by helper T cells, which then activate cytotoxic T cells to kill the donor cells.

(C) They induce the production of blocking antibodies that protect the graft.

(D) They induce IgE, which mediates graft rejection.

17. Grafts between genetically identical individuals (i.e., identical twins):

(A) Are rejected slowly as a result of minor histocompatibility antigens

(B) Are subject to hyperacute rejection

(C) Are not rejected, even without immunosuppression

(D) Are not rejected if a kidney is grafted, but skin grafts are rejected

18. Penicillin is a hapten in both humans and mice. To explore the hapten–carrier relationship, a mouse was injected with penicillin covalently bound to bovine serum albumin and, at the same time, with egg albumin to which no penicillin was bound. Of the following, which one will induce a secondary response to penicillin when injected into the mouse 1 month later?

(A) Penicillin

(B) Penicillin bound to egg albumin

(C) Egg albumin

(D) Bovine serum albumin

19. AIDS is caused by a human retrovirus that kills:

(A) B lymphocytes

(B) Lymphocyte stem cells

(C) CD4-positive T lymphocytes

(D) CD8-positive T lymphocytes

20. Chemically induced tumors have tumor-associated transplantation antigens that:

(A) Are always the same for a given carcinogen

(B) Are different for two tumors of different histologic type even if induced by the same carcinogen

(C) Are very strong antigens

(D) Do not induce an immune response

21. Polyomavirus (a DNA virus) causes tumors in “nude mice” (nude mice do not have a thymus because of a genetic defect) but not in normal mice. The BEST interpretation is that:

(A) Macrophages are required to reject polyomavirus-induced tumors

(B) Natural killer cells can reject polyomavirus-induced tumors without help from T lymphocytes

(C) T lymphocytes play an important role in the rejection of polyomavirusinduced tumors

(D) B lymphocytes play no role in rejection of polyomavirus-induced tumors

22. C3 is cleaved to form C3a and C3b by C3 convertase. C3b is involved in all of the following EXCEPT:

(A) Increasing vascular permeability

(B) Promoting phagocytosis

(C) Forming alternative-pathway C3 convertase

(D) Forming C5 convertase

23. After binding to its specific antigen, a B lymphocyte may switch its:

(A) Immunoglobulin light chain isotype

(B) Immunoglobulin heavy chain class

(C) Variable region of the immunoglobulin heavy chain

(D) Constant region of the immunoglobulin light chain

24. Diversity is an important feature of the immune system. Which one of the following statements about it is INCORRECT?

(A) Humans can make antibodies with about 108 different VH × VL combinations.

(B) A single cell can synthesize IgM antibody then switch to IgA antibody.

(C) The hematopoietic stem cell carries the genetic potential to create more than 104 immunoglobulin genes.

(D) A single B lymphocyte can produce antibodies of many different specificities, but a plasma cell is monospecific.

25.  C3a and C5a can cause:

(A) Bacterial lysis

(B) Vascular permeability

(C) Phagocytosis of IgE-coated bacteria

(D) Aggregation of C4 and C2