Type I hypersensitivity is due to release of inflammatory mediators from_____, and type IV hypersensitivity is due to the actions of_____.

a. T_H cells; macrophages

b. neutrophils; T_H cells

c. B cells; T_C cells

d. mast cells; T_H cells

Lymphocytes that develop immunocompetence in the bone marrow are:

a. T lymphocytes

b. B lymphocytes

c. NK cells

d. B and T lymphocytes

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

In the primary immune response, the lag phase lasts about 5 days, during which time B cells proliferate and differentiate.

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.

Give a function for each of the following:

(a) Cytotoxic T cells

(b) Helper T cells

(c) Regulatory T cells

(d) Plasma cells

(e) NK cells

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