In vitro sensitization to transplantation antigens : VI. Inhibition of sensitization

We have previously reported that C57BL/6 lymph node cells cultured with C3H/He macrophage monolayers are subsequently able to transfer specific allograft immunity to recipient C57 mice. The present communication is an investigation of the requirement for the functional integrity of cells to mediate allosensitization in vitro and to transfer allograft immunity. Our results indicate that C3H macrophage monolayers subjected to X-irradiation, actinomycin D, or antimacrophage serum pretreatment can no longer sensitize C57 lymph node cells in vitro; supernatants of C3H macrophage cultures do not substitute for monolayered cells and cannot sensitize C57 lymph node cells. The present data also indicate that the integrity of the lymph node cells is required after sensitization in vitro: X-irradiated or sonicated allosensitized lymph node cells do not enable recipient mice to accelerate C3H allograft rejection. The results of this report, therefore, suggest that intact, functionally normal cells are required to sensitize, and to transfer allosensitization.