title: Evidence for a B-cell -like helper function in mixed lymphocyte culture between immunocompetent thymus cells.
abstract: The immunocompetent subpopulation by mouse thymus cell (TH-2) was isolated by buoyant density centrifugation and by hydrocortisone pretreatment. TH-2 cells undergo a proliferative one-way or two-way mixed lymphocyte culture (MLC) response only when cultured with allogeneic or congenic peripheral lymphoid cells. However, mixtures of allogeneic TH-2 cells alone do not proliferate in either one-way or two-way MLC reactions. Such MLC mixtures are proliferative only if mitomycin-blocked peripheral lymphoid cells are also present in the mixture. The peripheral helper cell has been found to be of low net density, non-adherent, insensitive to anti-thy-1 serum cytotoxicity, but sensitive to the cytotoxic effets of anti-immunoglobulin serume plus complement. The helper effect does not depend on proliferation nor does it appear to involve demonstrable soluble mediators. The nature of failure of MLC between TH-2 subpopulations appears to be dependent on the exppression of some product of the K, I regions of the H-2 locus. Possible mechanisms by which a B-cell-like helper cell triggers TH-2 proliferation are discussed terms of the present knowledge of specific alloantigen receptor on T and B cells, and the immunoglobulin Fc region receptors on T cells.
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D002455:Cell Division; D002469:Cell Separation; D002499:Centrifugation, Density Gradient; D005260:Female; D006854:Hydrocortisone; D007519:Isoantigens; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008810:Mice, Inbred C57BL; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D007519:Isoantigens; D006854:Hydrocortisone