Primary Versus Secondary Response Immunohematology Review 434
PRIMARY SECONDARY (ANAMNESTIC)
Stimulus 1st exposure to ag Subsequent exposure to ag
Lag phase Days to months Hours
Type of antibody IgM at first. May switch to IgG after 2–3 weeks IgG
(isotype switching)
Titer Rises slowly, peaks, then declines Rises faster & higher, stays elevated longer
PRIMARY SECONDARY
Steady state
Total Ab
Logarithmicincrease
IgM
IgG
Antibody Concentration in SerumInductive period
Decline
Total Ab
IgG
NegativeIgM
phase
Primaryimmunogenic
stimulation
Secondaryimmunogenic
stimulation
Schematic representation of primary and secondary antibody responses. Note the enhanced antibody
production and expanded antibody-producing cell population during the secondary antibody response.
(From Herscowitz HB. Immunophysiology. In Bellanti JA [ed]: Immunology III. Philadelphia: WB Saunders; 1985:117, with permission.)
