288 Anatomy, Histology, and Cell Biology
of plasma cells from B cells, they are notdirectly involved in antibody pro-
duction. Also note, B cells can present antigen in addition to the more tra-
ditional APCs.
182.The answer is e.(Kindt, pp 289–290, 481–484. Alberts, pp 1370–1371.
Abbas, pp 144, 146.)The goal of all vaccines is to promote a primary immune
reaction so that when the organism is again exposed to the antigen, a much
stronger secondary immune response will be elicited. Any subsequent
immune response to an antigen is called a secondary response. A secondary
immune response is more rapid, of longer duration, and more intense than
the primary immune response (answers a, b, and d).The secondary
response is more specific to the invading antigen because of the generation of
memory cells produced during the primary response. The design of an
immunizing vaccine hinges on the specificity and cross-reactivity of antigen
and receptor. Vaccines are more effective and long-lived when live attenu-
ated virus is used to develop the vaccine. Vaccines developed to inactivated
virus are not as effective. Live attenuated virus undergoes limited replication
in the host cells resulting in a strong, site-specific response to the antigen.
Anthrax vaccine is made to inactivated virus and requires boosters at yearly
intervals. The primary immune response involves primarily IgM while the
secondary response predominantly involves IgG antibodies (answer c).
Humoral immunity and cell-mediated immunity involve retention of
immunologic memory through memory B and T cells, respectively. A sec-
ondary immune response may involve memory T cells, helper cells,
macrophages, and memory B cells. The proliferation of either T or B cells
during the first exposure to antigen results in the production of memory
cells. Specificity is retained. For example, the introduction of a different
(new) antigen induces a primary rather than a secondary response. However,
exposure to an antigen again, will produce a secondary immune response.