Trypsin does not reconstitute responsiveness to lipopolysaccharide in the strain C3H/HeJ, but is a B-cell mitogen-like lipopolysaccharide, stimulating a different subpopulation.
The effect of trypsin on mouse spleen cells and enriched B cells, added alone or together with lipopolysaccharide (LPS), was investigated. With trypsin, proliferation in serum free spleen cell cultures was 2-6 times greater than the background using cells from LPS responder strains, and 2-4 times the background with cells from the C3H/HeJ strain. Trypsin also induced the formation of a low number of IgM plaque forming cells (PFC). When added together with LPS, trypsin increased the proliferation caused by LPS alone by 10-50% with cells from LPS responder strains and by 50-100% with cells from the LPS non-responder strain C3H/HeJ. Trypsin enhanced proliferation in cultures maximally stimulated by LPS. The increased proliferation obtained when trypsin was added to LPS-stimulation of cells from the C3H/HeJ strain, was therefore not interpreted as a reconstitution of the LPS response. We conclude that trypsin has a moderate mitogenic effect on mouse B cells, stimulating the cells to proliferate and secrete IgM. The mechanism of action is unknown, but is different and independent from the action of LPS.
Cardell
S
S
Department of Immunology, Arrhenius Laboratories for Natural Sciences, University of Stockholm, Sweden.
Möller
G
G
D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D002478:Cells, Cultured; D007075:Immunoglobulin M / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects*; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008934:Mitogens / Q000494:pharmacology*; D014357:Trypsin / Q000494:pharmacology*
D007075:Immunoglobulin M; D008070:Lipopolysaccharides; D008934:Mitogens; D014357:Trypsin