Variations in Rabbit Antimouse Lymphocyte Sera Due to Strain Differences and “Nonthymic” Lymphocytes

Heterologous antimouse lymphocyte sera were evoked by injecting rabbits with normal mouse thymuses and lymph nodes (ATS and ALS), as well as lymph nodes of mice thymectomized and X-irradiated, and then immunized with typhoid-paratyphoid vaccine (NTALS). Antisera were raised against C57BL/6, Ajax, and C₃H inbred mouse strains. The effects were tested on skin allograft survival and peripheral lymphocyte counts. Allograft survival was more prolonged in recipients injected with antisera raised against the donor strains, while peripheral lymphocyte counts were more depressed if the antisera were directed against the recipient strains. While there was minimal prolongation of allograft survival if NTALS was raised against the donor strain, there were no effects of NTALS in any other strain combination, and no significant depression of the lymphocyte counts. Leukoagglutinin titers of ALS, ATS, and NTALS were equal when tested against mouse lymph node lymphocytes. It is suggested that enhancement could have been a factor in the prolongation of allograft survival when antisera were directed against the donor strain.