Heterogeneity of B Cells: Direct Evidence of Selective Triggering of Distinct Subpopulations by Polyclonal Activators

Abstract

This study was done to assess whether distinct subsets of B [bone marrow-derived] cells in the adult mouse spleen are selectively triggered by different polyclonal B-cell activators (PBA). Several strains of mice and [Escherichia-coli] lipopolysaccharide (LPS), purified protein derivative of tuberculin (PPD) and dextran sulfate (DS) were used in this study. Two experimental approaches used were stimulation after addition of 2 PBAs simultaneously to cell cultures; and eliminating the responding population to 1 PBA, by a hot pulse of radioactive thymidine, to study a later response to another PBA. DS apparently stimulated a cell population completely different from that stimulated by the LPS- and PPD-sensitive cells. When LPS and PPD stimulations were compared, the cells responding to these PBAs were largely distinct, although some cells were sensitive to both these PBAs. The extension of the overlaps in these subsets (the number of cells that could be activated by either PBA) varied from 1 strain to another. Subsets probably exist that can be activated by different PBAs. The functional performance of distinct subsets of B cells on activation was indicated.