Human placental cells that regulate lymphocyte function.
We examined normal human placenta for an immunologic function by measuring the release of soluble inhibitory factor (SIF). SIF is a product of normal T lymphocytes and of the JEG-3 choriocarcinoma cell line, and blocks proliferative and antibody-producing responses of mononuclear cells. SIF can be further characterized by a noncovalently linked subcomponent, lipid suppressor substance. The villous surfaces of six normal human placentae were digested with collagenase to obtain a population of predominantly multinucleated giant cells. These cells were maintained in standard culture for 5 days after which the cell-free conditioned culture medium was assayed for SIF content by measuring suppression of [3H]thymidine incorporation into lymphocytes stimulated by low-dose phytohemagglutinin. Undiluted placental SIF induced 88% inhibition of this response (p less than 0.001). The placental SIF was found to contain lipid suppressor substance, as does SIF from mononuclear cells. We determined this by thin-layer chromatography where a peak of suppressive activity occurred at Rf 0.32 [( 3H]thymidine incorporation reduced from 21810 +/- 308 to 4121 +/- 214 cpm); this is the position on thin-layer chromatography to which mononuclear cell lipid suppressor substance migrates. Ion exchange chromatography comparing the elution patterns of lymphocyte-SIF and placental-SIF indicated that both eluted in the fraction of 40-50 mM PO4 means buffer, further suggesting identity between these two substances. SIF from placental and lymphocyte sources functioned by inducing the presence of suppressor cells in culture.(ABSTRACT TRUNCATED AT 250 WORDS)
Wolf
R L
RL
Department of Pediatrics, Michael Reese Hospital and Medical Center, Chicago, Illinois.
D002478:Cells, Cultured; D002824:Chorionic Villi / Q000378:metabolism*; D005260:Female; D006801:Humans; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000378:metabolism; D011247:Pregnancy; D013491:Suppressor Factors, Immunologic / Q000378:metabolism; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism*
D008222:Lymphokines; D013491:Suppressor Factors, Immunologic