MONOCYTE-DEPENDENT STIMULATION OF HUMAN T-CELLS BY SILICON DIOXIDE

Mononuclear cells were isolated by Ficoll-Hypaque density gradient cen trifugation from randomly selected silicone breast implant recipients for testing. Restricted antibody to HLA-DR (28-33 kD) depleted the con canavalin A mitogenic response which was expected but failed to inhibi t the proliferative response to silicon dioxide. Further testing with monoclonal antibodies to HLA-DP, -DQ, and a second -DR with specificit y for the NS1 region of the MHC class II genome, all markedly inhibite d proliferation of T cells despite otherwise adequate stimulation by c oncanavalin A or silicon dioxide. Monoclonal antibodies directed again st B7-1 also inhibited proliferation of T cells following stimulation with concanavalin a or silicon dioxide. These results confirm the T-ce ll response to silicon dioxide is monocyte-dependent and not a superan tigen as has been speculated.