Transfer factor.

It has been more than 30 years since Dr. H. S. Lawrence first reported that it was possible to transfer delayed-type hypersensitivity from sensitized donors to unsensitized recipients with lysates of blood leukocytes. During recent years, research from several laboratories has demonstrated that this effect is immunologically specific. Although the molecules that possess this activity have not been completely characterized, there is a significant body of evidence that they are small polypeptides and that they can interact with antigen molecules in an immunologically specific manner. Studies with immune responses that are under genetic control have demonstrated that the ability of an animal to produce transfer factor is genetically regulated but that transfer of delayed hypersensitivity with transfer factor is not genetically restricted. In fact, when mice of low-responder phenotypes are administered transfer factor from high-responder donors, they express delayed hypersensitivity responses that are comparable to the high responders. Clinical studies have demonstrated that transfer factor is an efficacious method for immunotherapy of certain viral and fungal infections.