Transfer factor 1993: New frontiers

Adoptive transfer of antigen-specific cell-mediated immunity in humans, first demonstrated by Lawrence [1] in 1949, opened a new avenue of research that has led both to increased understanding of basic immune mechanisms and to the development of many forms of immunomodulant therapy, alone or in combination with other immu-notherapeutic or chemotherapeutic agents. Lawrence originally showed that transfer of intact viable lymphocytes from a normal tuberculin skin test-positive donor for a given antigen to a normal recipient, skin test-negative for that antigen, resulted in a conversion (“transfer”) of the recipient to skin-test positivity; however, this observation created little interest in the immunologic community for several reasons. In 1955, the lymphocyte was mentioned for the first time as an immunologic organ. (Before this, the lymphocyte had been studied in hematologic rather than in immunologic terms.)