title: The ability of placental extracts to modulate a direct PFC response to SRBCs in mice.
abstract: Placental extracts were injected in conjunction with sheep or pigeon RBC to CBA female mice. Spleen cells from these animals were then transferred to isogeneic recipients. The immune response of these recipients, actively immunized towards the immunogen used for priming of cell donors, was studied. (1) It was shown that placental extracts were most efficient in inducing suppressor cell activity in a direct (IgM) plaque-forming assay when injected simultaneously with the immunogen used for cell donor priming. (2) Suppressor cells were generated both in anti-SRBC and anti-PRBC reactions and suppressed the corresponding IgM response after transfer to isogeneic recipients. (3) Combined experiments consisting of the transfer of cells, primed by either SRBC or PRBC, into recipients immunized with a mixture of both immunogens, resulted in a selective suppression of the response directed against the type of RBCs used for the induction of suppressor cells. Results are discussed in the light of previous experiments from this and other laboratories, which showed suppressor effects of placental extracts operating in transplantation systems.
mesh_terms: D000818:Animals; D000921:Antibody-Producing Cells / Q000276:immunology*; D000941:Antigens / Q000008:administration & dosage; D010856:Columbidae; D000939:Epitopes; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D006462:Hemolytic Plaque Technique; D007116:Immunization, Passive; D051379:Mice; D008805:Mice, Inbred A; D008808:Mice, Inbred CBA; D010924:Placental Extracts / Q000008:administration & dosage / Q000276:immunology*; D012756:Sheep; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000941:Antigens; D000939:Epitopes; D010924:Placental Extracts