The biological effects of allogeneic effect factor (AEF) on T lymphocytes. III.--Interferon does not contribute to the biological activities displayed by AEF on both T and B lymphocytes.

The studies reported here were designed to evaluate the potential contribution of interferon (IF) to the biological activities mediated by allogeneic effect factor (AEF), a soluble product of allogeneic cell interactions, on responses of T and B lymphocytes. AEF supernatants were found to contain varying levels of IF, predominantly of type II (immune). AEF preparations which were practically free of--or very low in--IF activity were obtained by bovine serum albumin-Sepharose chromatography of AEF, or by using strain combinations involving K-only or I-only differences within the H-2 complex for the production of AEF. Such preparations retained their biological activities in three in vitro assays characteristic of AEF: (a) induction of primary self-H-2-reactive cytotoxic T-lymphocyte responses, (b) mitogenicity for normal T cells, and (c) induction of plaque-forming cell antibody responses to a T-dependent antigen in T-cell-depleted spleen cultures. These results demonstrate that IF does not play any significant role in the biological activities medicated by AEF.