The kinetics of IgG and IgM antibody-forming cells in ACI and F344 rats immunized with poly(glu52lys33tyr15).

The cellular kinetics of antibody production in high and low responder rats immunized with poly(Glu52Lys33Tyr15) or with poly(Glu52Lys33Tyr15)/MeBSA were characterized: serum antibody and IgG and IgM antibody-forming cells in the spleen and in selected lymph nodes were assayed in male and female rats following immunization by several routes. Aggregation of the antigen with MeBSA enabled the poorly responding F344 rats to produce antibody, which was almost exclusively IgG. High responder ACI rats, under the same conditions, produced antibody of both IgG AND IgM classes. These data suggest that in low responders one defect, possibly at the T-cell level, can be overcome by aggregation but that a second defect, involving the regulation of IgM production, still exists.