EFFECTS OF THE WHOLE EXTRACT AND THE CHROMATOGRAPHIC FRACTIONS OF THEPIG PLACENTA ON LYMPHOCYTE-PROLIFERATION AND HUMORAL IMMUNE-RESPONSE

The immunoregulatory properties of pig fetal placenta extracts (PE) fr om 1st, 2nd and 3rd month of pregnancy and five fractions (F1 to F5), isolated on Sephadex G-200 and additionally characterized by fast perf ormance liquid chromatography, FPLC (Superose 12 HR) were studied in o rder to clarify the local immune regulation in diffuse eiptheliochoria l placentation. The obtained substances were added at 6.25 to 100 mu g in cultures of Concanavalin A-stimulated mouse splenocytes and Phytoh emagglutinin-stimulated pig and human PBL to monitor their influence o n [H-3]Thimidine uptake in proliferating lymphocytes. Their effects on the number of plaque-forming cells in spleen cell suspensions from mi ce treated ip simultaneously with sheep red blood cells and with 100 m u g protein of PE, respectively of each fraction were also investigate d: PE and Fl had no effect while F4 and F5 suppressed the mitogen-indu ced lymphocyte proliferation in all studied species. F2 and F3 stimula ted mouse and pig lymphocyte proliferation. The effects were dose-depe ndent and the suppression was not due to cytotoxic effects. The FPLC d ata allowed the suggestion that 110 kD protein(s) were involved in sti mulation and 7 kD substance(s) in suppression of cell proliferation. T he PE from the 3 studied periods as well as the 5 fractions increased significantly the primary humoral immune response against T-dependent antigen. The results revealed that trophoblast of epitheliochorial pla centa produces simultaneously immune-stimulatory and -suppressive fact ors acting across the species barrier. Their presence at the fete-mate rnal interface may contribute to the regulation of local immune reacti ons and survival of the allogenic fetuses despite the morphological sp ecificities of this type of placentation.