1989 Volume 35 Issue 6 Pages 1391-1405
Non-specific cytotoxic activity induced by Interleukin-2 (IL-2) was examined in the lymphoid tissues including the spleen, thymus and bone marrow. High cytotoxic activity against YAC-1 cells was induced by IL-2 in cells from all the lymphoid tissues but cytotoxic activity against P815 were rarely detected in bone marrow cells. In the thymocytes which contain T cells in various differentiation stages, it was demonstrated that Thy-1+ L3T4 (CD4)-Lyt-2 (CD8)- cells were induced by IL-2 to express cytotoxic activity against YAC-1 but not against P815 in the embryo and adult mice. On the contary, IL-2 induced cytotoxic activity against P815 was found in the L3T4-Lyt-2+ adult thymocytes but such activity was scarcely detectable in the same phenotype thymocytes of 15 day embryos which were induced by IL-2 during 6 day-organ culture. The Thy-1+L3T4- Lyt-2- cells obtained from nylon wool column passed spleen cells from athymic nude mice and SCID mouse thymocytes also showed high cytotoxic activity against YAC-1 but low activity against P815.
These results suggest that IL-2 can induce cytotoxic activity in the immature thymocytes against NK sensitive and the L3T4- Lyt-2+ mature T cells against both NK resistant and sensitive cells.