HLA-DR-specific suppressor cells after repeated allogeneic sensitizations of human lymphocytes in vitro.

In conclusion, DR-specific suppressor cells can be induced by repeated in vitro sensitizations. They were able (1) to decrease a secondary proliferation, (2) to suppress consistently, in a primary proliferative assay, when added as third cells (primed twice against a DR antigen [PLT II] and gamma-irradiated), the response of unprimed cells towards stimulating cells, which share a DR specificity with the priming cell of the PLT II. The suppression follows the D part of the recombinant haplotype within an HLA-B/D recombinant family and is specific for the DR antigen used twice as stimulator for production of the PLT II.