PGE2, but not TGF beta 2, in rabbit blastocoelic fluid regulates the cytotoxic activities of NK and LAK cells.
Spontaneous and induced fetal resorptions have been associated with the infiltration and activation of GM1-positive natural killer (NK)-like cells. Predominance of these cells in the decidua and their reduced lytic activity suggest that regulation of their killing activity could be important for the survival of the fetus. It has therefore been hypothesized that the embryo was regulating NK lytic activity. To test this hypothesis, human and rabbit lymphocytes were cultured with various concentrations of interleukin-2. Their ability to kill 51Cr-labelled NK and lymphokine-activated killer (LAK)-sensitive targets was assessed in the presence of rabbit blastocoelic fluid taken at day-12 of pregnancy (BF D-12). BF D-12 dramatically suppressed the killing activity of NK and LAK cells. This effect was observed on K562 (NK-sensitive targets), P815 cells (LAK-sensitive targets), and freshly isolated cells in rabbit trophoblastic cell preparation. Elimination of prostaglandin E2 (PGE2), but not transforming growth factor beta 2 (TGF beta 2) or 6 keto prostaglandin F1 alpha (6KPGF 1 alpha), by affinity chromatography, completely abolished BF biological activity. These findings clearly suggest that PGE2 in BF regulates the killing activity of NK and LAK cells, and that the semiallograft embryo plays an active role in its own protection. To our knowledge, it is the first demonstration that PGE2 from the embryo inhibits NK and LAK cell lytic activity.
Bergeron
D
D
Department of Obstetrics and Gynecology, Laval University, CHUL Research Center, Ste-Foy, Québec, Canada.
Ouellette
M J
MJ
Lambert
R D
RD
D000818:Animals; D001755:Blastocyst / Q000378:metabolism* / Q000502:physiology*; D001826:Body Fluids / Q000378:metabolism / Q000502:physiology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects; D015232:Dinoprostone / Q000032:analysis / Q000502:physiology*; D005260:Female; D006801:Humans; D015979:Killer Cells, Lymphokine-Activated / Q000187:drug effects / Q000276:immunology*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive; D008213:Lymphocyte Activation / Q000187:drug effects; D012515:Mast-Cell Sarcoma; D051379:Mice; D011247:Pregnancy; D011817:Rabbits; D016212:Transforming Growth Factor beta / Q000032:analysis / Q000502:physiology*; D014407:Tumor Cells, Cultured
D016212:Transforming Growth Factor beta; D015232:Dinoprostone