The relationship between surface immunoglobulin isotype and immune function of murine B lymphocytes II. Surface immunoglobulin isotopes on unprimed B cells in the spleen.

Abstract

The ability of Ig[immunoglobulin]M-, IgD-, and IgG-bearing cells from the spleens of unprimed (BALB/c .times. C57BL/Ka)F1 mice to restore the adoptive primary anti-BSA [bovine serum albumin] and anti-DNP [dinitrophenol] antibody responses was investigated. Purified populations of isotype-specific cells were prepared by immunofluorescent staining and sorting on the fluorescence activated cell sorter. Bright or dull cells were transferred to irradiated syngeneic recipients which were challenged with DNP-BSA in complete Freund''s adjuvant. Unfractionated spleen cells as well as IgM- and IgD-bearing cells restored the adoptive primary IgM and IgG antibody response. IgG-bearing cells restored a vigorous adoptive response which was all IgG (2-mercaptoethanol resistant). Depletion of IgG-bearing cells markedly increased the adoptive IgM response, and depletion of IgM-bearing cells markedly increased the IgG response. Depletion of IgD-bearing cells resulted in a considerable reduction in the IgG response. There apparently is a subpopulation of IgD-bearing cells which express little or no surface IgM and which make a considerable contribution to the adoptive primary IgG response.