Transfer factor: an overlooked potential for the prevention and treatment of infectious diseases.

Transfer factor (TF) is a low-molecular-weight lymphocyte extract capable of transferring antigen-specific cell-mediated immunity (CMI) to T lymphocytes. It has been used successfully as an adjuvant or primary therapy for viral, parasitic, fungal, and some bacterial infections, as well as immunodeficiencies, neoplasias, allergies and autoimmune diseases. From the list of infections that seem to respond noticeably to transfer factor, those due to viruses of the herpes family are particularly remarkable. Indeed, for these viruses it was shown that TF can prevent infection or relapse, acting as a CMI vaccine. Data also suggest its possible use for adjuvant treatment and probably prevention of two currently widespread infections: tuberculosis and AIDS. Furthermore, TF has an interesting potential: answering the challenge from unknown pathogenic agents, a black box effect permitting production of antigen-specific TF to a new pathogen, even before its identification. It thus seems that the preventative potential of transfer factor is as important as its therapeutic one, both discussed in this review.