The first phase of antigen removal takes only 10 to 20 m____s and represents
time required for e____bration of the antigen with the tissues and fluids. Nearly
90% of the antigen is removed from the circulation in its first passage through
the___r, ___s, and s___n by extensive p_____osis.
The second phase of antigen elimination is a phase of gradual ____bolic
degradation and r____al. This phase lasts for 4 to 7 ____s and represents the
gradual enzymatic h___sis and d_____n of the antigen.
During the third phase, removal of antigen is a_____ated by the combination of
newly formed ____y molecules with the _____en, enhancing _____is.
A primary immune response occurs when an individual first en_____rs a foreign
antigen. After antigen exposure, there is a lag of several hours to several days
before antibody is detected. This latent period depends upon the kind and
_____nt of antigen given, the ___te of administration, and other h__t-dependent
factors. Antibody appears between the fifth and tenth ____y.
After the first exposure to an antigen, the lag before response is called the l___nt
period. This lag is due to two factors. First, it may take several days before
enough antibody is produced for it to be m____ble. Second, the first antibody
molecules may be excreted in combination with r___dual antigen and thus not
After the latent period ends, the primary antibody response becomes d____e. The
titer of antibody gradually in____s over a period of a few days to a few weeks,
plateaus, and then b__s to d__p. The initial antibody formed in the primary
response is ___. During the first and second week, IgM production ____s.
Evidence suggests that a single precursor B cell can give rise to a cl___e, which
can switch from IgM to ___ production. This phenomenon is referred to as the
Ig_-Ig_ shift. IgG production declines after a few ____s.
With subsequent exposure to antigen, the antibody response differs dramatically
from the primary antibody response. This secondary response is characterized by
a sharp ___p in circulating antibody because it c____xes with the newly injected
a____n. Immediately thereafter, a marked (decrease) (increase) in antibody levels
becomes evident; the antibody is primarily Ig_. Ultimately, the titer far surpasses
that of the primary response and has a more extended d____n.
Current theories of immunoglobulin formation include c___l s___tion theory and
temp___ or ____tive theory.