HLA control of interferon production in the human mixed lymphocyte culture

This report describes studies of interferon production in the human mixed lymphocyte culture. Similar levels of interferon were detectable in two-way, unidirectional, and double-irradiated mixed lymphocyte culture combinations. Following an initial lag period of 1-2 days interferon production showed a peak response on days 3-4 and, in most combinations, was detectable through day 7 of the mixed lymphocyte culture. Interferon-gamma was the predominant type of interferon produced, along with a minor component of interferon activity detectable in some culture combinations which appeared similar to interferon-alpha. Interferon was not produced in HLA identical sibling combinations except for one brother-sister pair who were the donor and recipient of a kidney allograft. Interferon was produced in sibling and unrelated individual combinations that expressed HLA-A, HLA-B, or HLA-DR region incompatibility, with higher concentrations of interferon detectable in the HLA-DR region imcompatible combinations.