title: Differential effect of isolated placental isoferritins on in vitro T-lymphocyte function.
abstract: The effect of isoferritins isolated from human term placenta on certain T-lymphocyte parameters was studied in vitro using normal human lymphocytes. These isoferritins differed in ion exchange affinity, isoelectric point, and subunit composition. Only the acidic isoferritins caused a marked suppression of phytohaemagglutinin (PHA) blastogenesis and the most acidic isoferritin ('Acid I') was suppressive at a concentration as low as 0.25 microgram/ml. All four isoferritins suppressed concanavalin A (Con A) blastogenesis in a similar concentration dependent manner, with maximum effect at an isoferritin concentration of 1 microgram/ml. Both basic and acidic isoferritins reduced the Con-A-capping phenomenon in normal lymphocytes at concentrations higher than 0.5 microgram/ml, but at 0.25 microgram/ml only the acidic isoferritin was effective. The above findings support our previous report concerning the suppressive effect of splenic ferritin on T-lymphocyte function in vitro and indicate that acidic isoferritins, which often predominate in malignancy, demonstrate a higher degree of immunosuppressive activity. Thus, acidic isoferritins may play a role in the development of abnormal lymphocyte function encountered in certain proliferative disorders.
mesh_terms: D003208:Concanavalin A / Q000494:pharmacology; D004306:Dose-Response Relationship, Immunologic; D005293:Ferritins / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007108:Immune Tolerance / Q000187:drug effects; D007152:Immunologic Capping / Q000187:drug effects; D066298:In Vitro Techniques; D008213:Lymphocyte Activation / Q000187:drug effects*; D010835:Phytohemagglutinins / Q000494:pharmacology; D010920:Placenta / Q000032:analysis*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D010835:Phytohemagglutinins; D003208:Concanavalin A; D005293:Ferritins