21. The Immune System

Perforins are proteins associated with the activity of

(a) T cells

(b) B cells

(c) NK cells

(d) Plasma cells

Class I MHC molecules display_____antigens and activate_____cells. Class II MHC molecules display _____antigens and activate_____cells.

Which of the following conditions may lead to the development of autoimmunity?

a. Self antigens not previously encountered by T cells are released into the circulation

b. Foreign antigens mimic self antigens

c. Cells may inappropriately display class II MHC molecules

d. Certain pathogens nonspecifically activate B cells

e. All of the above are correct

Which of the following is NOT a consequence of the immune system lacking an immune tolerance?

Mark the following statements as true or false. If a statement is false, correct it to make a true statement.

Cancer cells are destroyed by NK cells, T_C cells, and macrophages.

How does a cytotoxic T cell destroy another cell displaying antigens bound to class I MHC proteins?

Where do T cells undergo central tolerance selection?

Define immunocompetence and self-tolerance. How is self-tolerance achieved?

The cell type most often invaded by HIV is a(n):

a. Eosinophil

b. Cytotoxic T cell

c. Natural killer cell

d. Helper T cell

e. B cell

Mr. White developed neutropenia as a consequence of cancer chemotherapy, which destroyed much of his bone marrow. What other components of the immune system would be harmed by bone marrow destruction? Would you expect his hematocrit to be elevated or decreased? What effects would you expect to see from this change in hematocrit?

Mark the following statements as true or false. If a statement is false, correct is to make a true statement.

The secondary immune response is mediated by plasma cells.

Blocking the antigen receptors on the surface of lymphocytes would interfere with

(a) Phagocytosis of the antigen

(b) That lymphocyte's ability to produce antibodies

(c) Antigen recognition

(d) The ability of the lymphocyte to present antigen

(e) Opsonization of the antigen

Skin tests are used to determine if a person 

(a) Has an active infection

(b) Has been exposed to a particular antigen

(c) Carries a particular antigen

(d) Has measles

(e) Can produce antibodies