Identification, functional characterization and partial purification of thymus-derived lymphocytes in inbred hamsters

Antiserum specific for hamster thymus-derived lymphocytes, prepared by immunization of rabbits with brain tissue from MHA/ssLAK hamsters, was, in the presence of guinea-pig complement, cytotoxic to hamster thymocytes greater than lymph node cells greater than spleen cells, while virtually unreactive against bone marrow cells. This antiserum markedely inhibited spleen cell response to the T cell mitogen, Concanavalin A, while the response to the B the T cell mitogen, pokeweed, was much less inhibited. These in vitro effects of the anti-hamster T cell serum were confirmed by utilizing lymphoid cells from thymectomized, lethally-irradiated, bone marrow-reconstituted hamsters. Lymph node cells from such animals were killed by the anti-T cell serum only to the same extent as bone marrow cells, while spleen cells from these animals gave a good response to pokeweek mitogen but were virtually unresponsive to Concanavalin A. Passage of hamster spleen cells over nylon wool columns yielded effluent populations highly enriched in T lymphocytes. The eluted cells were fully capable of T cell functions, as determined by their blastogenic response to various T and B cell mitogens in vitro and their ability to inhibit the growth of syngeneic SV40 tumours in vivo.