In vitro primary responses of human T cells to soluble protein antigens.

The optimum culture conditions to support in vitro proliferative responses to conventional soluble protein antigens by human CD4+ T cells from healthy non-immunised donors have been determined. These responses were blocked by anti-HLA-DR monoclonal antibodies (mAbs) and were strictly dependent on the presence of antigen-presenting cells (APCs). Primary responses showed a reproducible pattern of proliferation kinetics which distinguished them from secondary in vitro T cells reactions. T cells specific for the sensitising antigen were recovered from primary cultures.