Abstract
Gamma-interferon-induced HLA-DR-like antigens on normal human fibroblasts were compared functionally to HLA-DR antigens on peripheral blood mononuclear leucocytes (PBML) from the same individual. Irradiated DR+ fibroblasts did not stimulate allogeneic PBML to divide in a mixed lymphocyte fibroblast culture (MLFC) as determined by 3H-thymidine incorporation, although lymphocytes autologous to the fibroblasts stimulated normally. Co-culture with interleukin 1 (IL-1), IL-2, 2-mercaptoethanol and indomethacin had no effect on MLFC. Pretreatment of stimulator fibroblasts with neuraminidase to modify sialoglycoproteins increased responses only modestly. Both DR+ and DR- fibroblasts inhibited a normal mixed lymphocyte culture (MLC) response in a dose-dependent fashion. These results suggest that the induction of HLA-DR-like molecules on fibroblasts is not sufficient to initiate host sensitization and that fibroblasts may inhibit normal lymphoproliferation.