Lipopolysaccharide-induced immunomodulation of the generation cell-mediated cytotoxicity. II. Evidence for the involvement of a regulatory B lymphocyte

Daniel A Vallera, C. E. Gamble, J. R. Schmidtke

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Bacterial lipopolysaccharide (LPS) suppressed the development of cell-mediated cytotoxicity in vitro in a murine mixed lymphocyte culture (MLC) in which BALB/c splenocytes responded to x-rayed C57BL/6 stimulator cells. Addition of LPS at the initiation of MLC markedly suppressed the killing of labeled EL4 tumor target cells (C57BL/6 origin). Responder BALB/c cells were purified on nylon wood columns. In the presence of LPS and C57BL/6 stimulator cells, the BALB/c nonadherent, T enriched fraction (T-NWNA cells) was resistant to the suppressive effects of LPS. When T-NWNA and B-NWA cells were mixed and used as responders in the MLC, LPS exerted its reductive effect in the presence of B-NWA cells. Furthermore, proliferation of the B-NWA cells was a prerequisite for LPS-induced suppression of CMC since treatment of these cells with mitomycin C totally abrogated LPS-induced suppression of CMC. The involvement of B lymphocytes was further supported by the inability to demonstrate LPS induced suppression of CMC when C3H/HeJ cells were used as responders. The involvement of macrophages in this system was minimized. Despite separation of the BALB/c B-NWA cells from BALB/c T-NWNA cells and x-rayed C57BL/6 stimulator cells by an impermeable nucleopore membrane. LPS-induced suppression of CMC still occurred. These data suggest that LPS induced a factor from activated B cells that had a pronounced modulatory effect on the T cell subpopulation(s) involved in the generation of CMC in the murine MLC.

Original languageEnglish (US)
Pages (from-to)641-649
Number of pages9
JournalJournal of Immunology
Issue number2
StatePublished - Jan 1 1980


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