Characterization of human interferon-gamma-producing leukocytes with monoclonal antileukocyte antibodies.

Monoclonal antibodies with specificities for subsets of human leukocytes have been used for the characterization of interferon (IFN) gamma-producing cells. The production of IFN gamma was demonstrated to be a function of OKT3+T lymphocytes. The capacity to secrete IFN gamma was not restricted to the OKT4+ or the OKT8+T-cell subset. BA-1+B lymphocytes and Leu7+ natural killer cells did not contribute to the production of IFN gamma. Ia+, OKM1+ monocytes served an auxiliary function in the production of IFN gamma. The requirement for accessory monocytes, however, was not absolute, because monocyte-free preparations of long-term cultured IL2-dependent T lymphocytes retained the capacity to secrete IFN gamma.