| Abstract: | The separation of mouse splenic T lymphocytes into distinct subpopulations by fractionation on histamine-rabbit serum albumin Sepharose (H-RSAS) columns has been described. The H-RSAS-adherent T cells have been attributed regulatory functions associated with B cell activity, T cell-mediated cytotoxicity and the secretion of mediators such as immuno-interferon. The possibility that H-RSAS-adherent T cells exert a similar regulatory effect on an in vitro parameter of T cell-mediated immunity was investigated by assaying the production of leucocyte migration inhibition factor (LIF) in human blood samples, using the agarose droplet method. Phytohaemagglutinin (PHA) and BCG-purified protein derivative (PPD) were used as stimulants of LIF secretion which was measured as a percentage of inhibition of linear leucocytic migration. In normal individuals a highly significant (P less than 0.001) decrease was demonstrated in the production of LIF by peripheral blood leucocytes depleted of H-RSAS-adherent cells. Migration inhibition dropped from 36 +/- 11.7% to 21.2 +/- 12.9% in eighteen cases tested with PHA and from 29.3 +/- 11.7% to 17.2 +/- 9.8% in twelve cases tested with PPD. These results suggest the existence of a lymphocytic subpopulation involved in LIF production which expresses histamine receptors. |
