title: Pregnancy-associated exosomes and their modulation of T cell signaling.
abstract: Exosome release by viable cells is a feature of activated cell types, including tumors, fetal cells, and cells of the immune system. Exosomes critically regulate immune activation, by mediating activation-induced cell death. Fetal cells may mimic these events to selectively delete reactive lymphocytes. In this study the presence and composition of placenta-derived exosomes are demonstrated in the maternal circulation along with their consequences on T cell activation markers. For all pregnant patients, exosomes were isolated from sera obtained between 28 and 30 wk gestation. For pregnant women, subsequently delivering at term, circulating levels of placental exosomes were 1.8 times greater than those delivering preterm (p < 0.0001). Exosomes isolated from pregnancies subsequently delivering at term expressed significantly higher levels of biologically active components, including Fas ligand (FasL) and HLA-DR, than those from pregnancies delivering preterm. Standardizing for protein concentrations, exosomes from term-delivering pregnancies exhibited greater suppression of CD3-zeta and JAK3 than those delivering preterm. The suppression of CD3-zeta and JAK3 correlated with exosome expression levels of FasL (r2= 0.92 and r2= 0.938, respectively). Fractionation of exosomes from term-delivering pregnancies by continuously eluting electrophoresis indicated that intact 42 kD FasL and an unidentified 24-kDa protein were associated with CD3-zeta suppression. Our results demonstrated that exosomes from pregnancies ultimately delivering at term are present at significantly greater concentrations than those from pregnancies delivering preterm; however, exosomes from term-delivering pregnancies also exhibit significantly greater suppression of CD3-zeta and JAK3.
authors.affiliation: Department of Obstetrics, Gynecology, and Women's Health, University of Louisville School of Medicine, Louisville, KY 40202, USA. ddtaylor@louisville.edu
authors.forename: Douglas D
authors.initials: DD
authors.lastname: Taylor
authors.forename: Sibel
authors.initials: S
authors.lastname: Akyol
authors.forename: Cicek
authors.initials: C
authors.lastname: Gercel-Taylor
mesh_terms: D000328:Adult; D017252:CD3 Complex / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D002847:Chromatography, Agarose; D015536:Down-Regulation / Q000276:immunology; D004591:Electrophoresis, Polyacrylamide Gel; D005089:Exocytosis / Q000276:immunology*; D053222:Fas Ligand Protein; D005260:Female; D006649:Histocompatibility Antigens / Q000097:blood; D006801:Humans; D007108:Immune Tolerance / Q000502:physiology; D007376:Interleukin-2 / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D053616:Janus Kinase 3; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000276:immunology; D008562:Membrane Glycoproteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000097:blood / Q000502:physiology*; D047928:Premature Birth / Q000097:blood / Q000276:immunology; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*; D000079424:Tumor Necrosis Factor Inhibitors; D048069:Tumor Necrosis Factors / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
chemical_list: D017252:CD3 Complex; C121704:CD3 antigen, zeta chain; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D006649:Histocompatibility Antigens; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D011257:Pregnancy Proteins; D000079424:Tumor Necrosis Factor Inhibitors; D048069:Tumor Necrosis Factors; D019014:fas Receptor; D011505:Protein-Tyrosine Kinases; C507933:JAK3 protein, human; D053616:Janus Kinase 3