Immunomodulation in guinea pigs by porcine spleen cell dialysate.

The effect of porcine spleen dialysate was studied on delayed-type hypersensitivity reactions, as well as on the phagocytic capacity and intracellular prostaglandin levels of peritoneal macrophages. Porcine spleen cell dialysate was fractionated on Sephadex G-10 and these fractions, as well as unfractionated dialysate, were injected intraperitoneally into antigen-primed guinea pigs. The guinea pigs were tested for delayed-type hypersensitivity towards PPD and SK-SD. The results show that unfractionated spleen cell dialysate augmented slightly the delayed-type hypersensitivity reactions, and after fractionation a significant augmentory activity was detected in two adjacent, early eluting fractions. This active elution region corresponds to the elution region where most of the guinea pig DTH augmenting activity of leukocyte dialysate is also detected. Furthermore, these fractions significantly augmented the phagocytic capacity of peritoneal macrophages, and decreased the intracellular levels of prostaglandin PGE2, thromboxan B2 and prostacyclin. These results indicate that porcine spleen cells from non-immunized animals can be used as a source for a non-specifically acting immunomodulatory preparation, which resembles that found in human leukocyte dialysate. These immunomodulatory substance(s) seem to operate via monocyte activation.