Transfer factor: recent developments in the pursuit of an idea

Effect of Brucella abortus transfer factor in preventing murine brucellosis

Mice vaccinated with a protein extract of attenuated Brucella abortus strain 19 had increased resistance to infection with virulent B. abortus strain 2308 and had increased antibody responses to strain 2308. However, resistance to infection and antibody responses were not increased when nonvaccinated recipient mice were given transfer factor preparations that were obtained from either vaccinated donor mice or strain 2308-infected donor mice. Vaccination of mice with the strain 19 extract plus treatment with each transfer factor preparation also did not further increase resistance to infection or antibody responses when compared with mice that received the vaccine alone. These results suggest that transfer factor from mice that have either vaccine-induced protective immunity to B. abortus or active B. abortus infections does not enhance antibody responses and resistance to infection with B. abortus.

Chromatographic and enzymatic effects on transfer factor-like activity from human leukocytes and porcine spleen dialysate

1. The effect of dialysable transfer factor (TFd), derived from human leukocytes or porcine spleen cells, was measured using Listeria resistance in mice. 2. The molecular weight range of substance(s) containing TF-like activity is in the less than 3500 MW dialysis fraction on the basis of the capacity of peritoneal macrophages to produce superoxide anion (O2-). This biological activity is removed by heating at 56 degrees C. 3. After Sephadex G-10 chromatography of dialysates the significant activities are found in fractions III and IV of human leukocyte dialysate and in fractions of II and III of porcine spleen dialysate. 4. From enzymatic studies, most of the protective activity of both human leukocyte and porcine spleen dialysate is based on the action of small-molecular weight structures containing peptides and/or polynucleotides.

Immunopotentiation against internal parasites

The economic importance of livestock losses attributed to internal parasites has led to the need of developing and successfully employing effective antiparasitic vaccines. An increasingly important strategy in the development of more effective vaccines is the preparation and use of immunopotentiators or adjuvants. Immunopotentiators or adjuvants have been used effectively in combination with antigen(s) or alone to protect animals against internal parasites. The use of immunopotentiators for specific and nonspecific stimulation of protective immunity against internal parasites is reviewed.