immune response

immune respones
dr. baha. hamdi.ai-amiedie ph. d.microbiology
primary immune response
during the primary response, when an individual encounters an antigen for the first time, antibody
response to that antigen is detectable in the serum after a longer time. the serum antibody concentration continues to rise for several weeks and then declines it may droping to very low levels. during this primary response, a small clone
of b cells and plasma cells specific for the antigen are.
formed lag period is typically of 7–10 days
first antibody formed is igm followed by igg

thesecondary immune response

the antibody response is typically more rapid in the secondary response, due to second encounter with,
the same antigen or a closely related “cross-reacting” antigen, months or years
after the primary response. the lag period is typically very short (only 3–5 days). the level of antibody is also much higher than that during the primary
these changes in secondary response are attributed to the persistence of antigen-specific “memory cells” following the first contact with the antigen. these memory cells proliferate in large
numbers to produce large clones of specific b cells and plasma cells that mediate the secondary response. in the secondary response