Mitotic response of rabbit peripheral blood lymphocytes to a factor in normal rabbit serum: a possible genetic polymorphism.

Normal rabbit sera contain a mitogen capable of stimulating rabbit peripheral blood lymphocytes in in vivo culture to incorporate radioactive thymidine. Cells from spleen, appendix or peritoneal exudate did not respond when cultured under similar conditions. The responding peripheral blood lymphocytes are adherent cells, but not macrophages. Presence of responding peripheral blood lymphocytes is a dominant trait. The response is regulated by a nonadherent, radiation-sensitive suppressor cell and by a nonadherent, relatively radiation-resistant helper cell.