Document Type

Article

Embargo Period

2-1-1981

Publication Date

2-1-1981

Abstract

Human peripheral blood B lymphocytes can be activated by pokeweed mitogen (PWM) 1, Staphylococcus aureus Cowan I, Epstein-Barr virus, or Nocardia water-soluble mitogen (1-4). Of these polyclonal activators, PWM and S. aureus have been shown to stimulate both B and T cells; furthermore, the activation of peripheral blood B cells by PWM appears to be T cell dependent (5, 6). Nocardia mitogen, Epstein-Barr virus, and S. aureus Cowan I have been shown to be relatively T cell-independent B cell activators (2-4). Several parameters can be used to evaluate the polyclonal "activation" of human peripheral blood B lymphocytes, including immunoglobulin (Ig) production in vitro, enumeration of Ig-secreting cells by reverse hemolytic plaque assay, and enumeration of intracytoplasmic Ig-containing cells in stimulated cultures. However, study of human peripheral blood B lymphocyte function in normal and disease states has been hampered by the failure of mature human B cells to respond to some classic activators of murine B cells, such as dextran sulfate, tuberculin (PPD), and Escherichia coli lipopolysaccharide (LPS) (7-10). Dextran sulfate activates relatively immature murine B cells and results predominantly in increased DNA synthesis; in contrast, PPD acts on relatively mature murine B cells and stimulates a marked increase in antibody production but only modest DNA synthesis (11). However, PPD and other polyclonal B cell activators (PBA) that activate mouse B cells do not have the same effects on human peripheral blood B lymphocytes. The ability to stimulate human B cells selectively would be of considerable value for studies of immune function. We describe here a "new" PBA, i.e., formaldehyde-fixed Salmonella paratyphi B, which activates human peripheral blood B cells to produce large amounts of Ig but does not stimulate DNA synthesis as measured by incorporation of tritiated thymidine. This PBA apparently acts on relatively mature B cells which differentiate into Ig-secreting cells without DNA synthesis. Furthermore, its action appears to be completely independent of T cells, since T-depleted cell populations respond well to formaldehyde-fixed S. paratyphi B.

Journal

Journal of Experimental Medicine

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