Cell surface immunoglobulin. XX. Antibody responsiveness of subpopulations of B lymphocytes bearing different isotypes.

Abstract

Murine spleen cells were depleted of specific B[bone marrow-derived]-cell subpopulations bearing different immunoglobulin [Ig] isotypes by means of complement-mediated cytolysis after treatment with antisera specific for .mu.- and .gamma.-chains. The functional effect of this depletion was measured by assaying the primary and secondary plaque-forming cell [PFC] responses of the residual cells after transfer to carrier-primed lethally irradiated hosts. Cells bearing IgM are probably the progenitors of PFC in the primary response cells bearing IgG may be the major progenitors of IgG PFC in the secondary response. The quantity of IgM on progenitors of secondary IgM PFC decreases markedly as the interval between primary immunization and antigenic challenge increases. Long-term memory cells for the secondary IgM response bear small amounts of IgM and IgG.