The activity of mitogenic factors generated in human mixed lymphocyte cultures (MLC-MF) was analyzed with unstimulated mononuclear leukocytes used as responder cells. Unseparated or adherent, but not nonadherent, irradiated, autologous mononuclear leukocytes were found to significantly enhance the mitogenic activity of MLC-MF. The effect of MLC-MF was not inhibited by hydrocortisone at concentrations that inhibited MLC-MF production, indicating that the MLC-MF effect is direct and is not mediated through further production of mitogenic factors. Experiments in which MLC-MF was produced in a MLC between a HLA-D homozygous individual and her child suggested that soluble alloantigens do not play a role in the MLC-MF effect. Studies in one individual with MLC responses higher than other individuals indicated average MLC-MF production but above average response to MLC-MF. We conclude that MLC-MF is directly mitogenic for unstimulated lymphocytes, without requiring the simultaneous presence of either mitogen or antigen. In addition, the proliferative MLC reaction of individuals with strong responses to MLC-MF may be influenced significantly by the nonspecific clones recruited by MLC-MF.
|Original language||English (US)|
|Number of pages||7|
|Journal||Journal of Immunology|
|State||Published - Jan 1 1982|
ASJC Scopus subject areas
- Immunology and Allergy