- B cells and helper T cells recognize the foreign
antigen; the B cells are antigen specific and begin
to divide. - Memory B cells will remember the specific foreign
antigen. - Other B cells become plasma cells that produce
antigen-specific antibodies. - An antigen–antibody complex is formed, which
attracts macrophages (opsonization). - Complement fixation is stimulated by antigen–
antibody complexes. The complement proteins
bind to the antigen–antibody complex and lyse cel-
lular antigens or enhance the phagocytosis of non-
cellular antigens.
Antibodies—immune globulins (Ig) or
gamma globulins (see Table 14–1 and
Fig. 14–8)
- Proteins produced by plasma cells in response to
foreign antigens. - Each antibody is specific for only one foreign anti-
gen.
3. Bond to the foreign antigen to label it for phagocy-
tosis (opsonization).
Antibody Responses and Functions (see Fig.
14–9)- On the first exposure to a foreign antigen, antibod-
ies are produced slowly and in small amounts, and
the person may develop clinical disease. - On the second exposure, the memory cells initiate
rapid production of large amounts of antibodies,
and a second case of the disease may be prevented.
This is the basis for the protection given by vac-
cines, which take the place of the first exposure. - Antibodies cause agglutination (clumping) of bac-
terial cells; clumped cells are easier for macro-
phages to phagocytize (see Fig. 14–8). - Antibodies neutralize viruses by bonding to them
and preventing their entry into cells. - Antibodies neutralize bacterial toxins by bonding
to them and changing their shape.
Types of Immunity (see Table 14–2)340 The Lymphatic System and Immunity
REVIEW QUESTIONS
- Explain the relationships among plasma, tissue
fluid, and lymph, in terms of movement of water
throughout the body. (p. 322) - Describe the system of lymph vessels. Explain how
lymph is kept moving in these vessels. Into which
veins is lymph emptied? (p. 322) - State the locations of the major groups of lymph
nodes, and explain their functions. (pp. 322–323) - State the locations of lymph nodules, and explain
their functions. (pp. 324) - Describe the location of the spleen and explain its
functions. If the spleen is removed, what organs
will compensate for its functions? (p. 324) - Explain the function of the thymus, and state when
(age). this function is most important. (pp. 324,
326) - Name the different kinds of foreign antigens to
which the immune system responds, and state three
general differences between innate immunity and
adaptive immunity. (p. 327)
8. Innate immunity includes barriers, defensive
cells, and chemicals; give two examples of each.
(p. 328)
9. Explain how a foreign antigen is recognized as
foreign. Which mechanism of adaptive immunity
involves antibody production? Explain what
opsonization means. (pp. 330, 333) - State the functions of helper T cells, cytotoxic
T cells, and memory T cells. Plasma cells
differentiate from which type of lymphocyte?
State the function of plasma cells. What other
type of cell comes from B lymphocytes? (pp. 330,
- What is the stimulus for complement fixation?
How does this process destroy cellular antigens
and non-cellular antigens? (pp. 334) - Explain the antibody reactions of agglutination
and neutralization. (p. 334) - Explain how a vaccine provides protective immu-
nity in terms of first and second exposures to a
pathogen. (p. 334)