Suppression of MLR and DTH responses in miniature swine by pretreatment with ultraviolet (UV)-irradiated peripheral blood lymphocytes.

Ultraviolet (UV)-irradiation of peripheral blood lymphocytes (PBL) of miniature swine prevented them from initiating proliferative responses in allogeneic mixed lymphocyte reactions (MLR). When pigs were given 4 weekly intravenous transfusions of UV-irradiated allogeneic donor PBL differing in major histocompatibility (MHC), PBL of recipient pigs progressively responded less vigorously to donor PBL in MLRs over the treatment period. These pigs did not produce anti-donor PBL antibody. Pigs treated with UV-irradiated PBL also had negligible delayed type hypersensitivity (DTH) responses to donor PBL at the end of the treatment period. In contrast, pigs receiving injections of untreated allogeneic PBL gave strong DTH responses to donor PBL, high proliferation in MLRs with donor PBL and all produced anti-donor PBL antibody.