A qualitative difference in the interleukin 2 (IL-2) requirement of helper and cytotoxic T lymphocytes

A qualitative difference in the requirement of mouse helper and cytotoxic T lymphocytes for interleukin 2 (IL-2) was revealed by offering such cells IL-2 synthesized in Xenopus laevis oocytes that had been microinjected with messenger RNA (mRNA) encoding human IL-2. While both helper and cytotoxic mouse T-cell lines proliferate in response to the IL-2 present in medium conditioned by stimulated human lymphocytes, only helper-T-cell lines respond to human IL-2 secreted from oocytes. This result demonstrates a difference between helper and cytotoxic T lymphocytes in their response to IL-2. The growth response of murine cells shows that IL-2 secreted from human cells has properties not found in the IL-2 secreted from oocytes, even though a monoclonal antibody directed against the human IL-2 receptor blocks the activity of both types of IL-2. Quite possibly, ths difference results from a post-translational modification.