Destruction of mouse and rat embryo cells in tissue culture by lymph node cells from unsensitized rats

Abstract A specific destruction of embryo monolayers was obtained in tissue culture, by growing suspensions of lymph node cells from unsensitized adult random bred rats, on mouse and on randomly bred rat monolayers. Mouse monolayers were lysed partially or completely in all the experiments. When two different batches of rat monolayers were used, the first batch was destroyed in three out of six experiments and the second in one out of five. The earliest destructive effect with unsensitized cells was observed on the sixth day. Destruction of monolayers followed the appearance of large numbers of large lymphoid cells with pyroninophilic cytoplasm. Cultures of unaffected rat monolayers were different, in that there was a prolonged survival of small lymphoctyes with the formation of lymphocyte aggregates in which large lymphoid cells appeared. When large lymphoid cells from destroyed monolayers were transferred to new monolayers of the same type, a complete destruction of the monolayers occurred as early as 16 hours after cell transfer, but when transferred to an unrelated type, (from mouse to rat or fom an unaffected batch of rat to the other batch or to mouse), the monolayers were not destroyed. The destructive effect was transferrable by washed large lymphoid cells, but not by cell‐free medium. There was no monolayer destruction with adult rat thymus cells. Tests for a possible viral injection as a contributing cause to the monolayer destruction were negative. The results indicate that a heterograft and a homograft response have been initiated in tissue culture by lymph node cells from unsensitized rats.