Name the five classes of immunoglobulins. Which is most likely to be found attached to a B cell membrane? Which is most abundant in plasma? Which is important in allergic responses? Which is the first Ig to be released during the primary response? Which can cross the placental barrier?

Binding of antigens to receptors of immunocompetent lymphocytes leads to clonal selection. Describe the process of clonal selection. What nonlymphocyte cell is a central actor in this process, and what is its function?

Interferons are referred to as antiviral proteins. What stimulates their production, and how do they protect uninfected cells?

Mrs. Morrow, a 59-year-old woman, has undergone a left radical mastectomy (removal of the left breast and left axillary lymph nodes and vessels). Her left arm is severely swollen and painful, and she is unable to raise it more than shoulder height.

(a) Explain her signs and symptoms.

(b) Can she expect relief from these symptoms in time? How so?

Mr. James, an 80-year-old man, is grumbling about having to receive a flu shot every year. Flu viruses have a high mutation rate (undergo rapid genetic changes), which results in the appearance of new proteins on the flu virus's 'coat.' How does this help explain the need to get a flu shot each year?

Describe the specific roles of helper, cytotoxic, and regulatory T cells in cell-mediated immunity. Which is thought to be disabled in AIDS?