Major histocompatibility complex class I antigens expressed on rat trophoblast cells

The use and misuse of animal analog models of human pregnancy disorders

It has been suggested that the differences between placentation in humans and rodents, such as mice, are sufficient to render human pregnancy unique and to justify ignoring data generated using mice. Detailed examination of the placenta-decidua interaction and decidual NK cell composition in humans, and mice, show that the principles are the same. Indeed, the rat placenta is useful in showing an intermediary arrangement between humans and mice. This is consistent with the thesis of Darwin that structures of older species evolve with development of new species to provide a survival advantage. Molecular details may differ between species, but also between individuals given gene polymorphisms. Human data on interaction of HLA-C2 with NK cell KIR receptors has been used to suggest that human pregnancy problems such as recurrent miscarriage, fetal growth retardation, and pre-eclampsia are due to lack of activation of true uterine NK cell (TuNK) functions that promote trophoblast cell growth and invasion which prevents such problems. But when TuNKs bear certain KIR phenotypes, pathology results. It is shown that such mechanisms could only be pertinent in less than one-third of recurrent miscarriage patients. Activated blood-type NK cells that enter the uterus (BuNKs) remain the major effector of pregnancy loss in humans, and this is consistent with data from the mouse. The importance of activated BuNKs in pre-eclampsia and fetal growth retardation merits further investigation as pre-eclampsia and fetal growth restriction are also manifest in the CBAxDBA/2 mouse model where activated NK cells are the initiator of abortions.

From the decidual cell internet: trophoblast-recognizing T cells

The mammalian fetus has been perceived, paradoxically, as a successful allograft, a successful tumor, and a successful parasite. Success depends on fetal trophoblast cells, which form the interface with the mother. The maternal immune system is involved in the success of pregnancy and in its failure. The discovery that maternal gammadelta T cells may recognize and react to the fetal trophoblast and the definition of a vascular mechanism whereby their Th1 and Th2/3-type cytokines may abort embryos replaces confusion and debate with a new and simple clarity that enables further research.

Human monoclonal antibody [1-1-2D] against cancer of the uterine cervix

To obtain a human monoclonal antibody (h-MAb) against cancer of the uterine cervix, lymphocytes from the regional lymph nodes of 14 patients with cervical cancer were fused with a mouse-human heterohybridoma [II]. Of 6,419 hybridomas, 1,295 produced human immunoglobulins (IgG 670, IgM 737). We isolated clone [1-1-2D], which has produced human IgM with stability for more than a year. This antibody reacted with three of five cell lines of cervical cancer but not with normal fibroblasts. Histoimmunostaining showed positive responses to 9/15 specimens of cervical cancer and in 2/7 specimens from cases of cervical dysplasia. Most of the normal human and fetal tissues showed no positive immune response. The positive immune response of [1-1-2D] to the cell membrane observed by the fluorescence antibody method disappeared after periodate treatment and was weakened by trypsin. Neuraminidase did not affect immune reactivity. This antibody showed a positive response by the thin-layer chromatography immunostaining method and precipitated a glycoprotein having a molecular weight of 38 kD. These results suggested that the epitope of the [1-1-2D] antibody is present on a carbohydrate moiety not containing sialic acid that is carried on protein and lipid moieties.

Analysis of the expression and immunostimulatory capacity of class I major histocompatibility antigens on rat trophoblast cell lines

In rat strains expressing the a and other major histocompatibility complex (MHC) haplotypes, subpopulations of placental trophoblast cells synthesize the nonclassical class I Pa antigen in preference to the classical RT1.Aa antigen. In this study, a rat trophoblast cell line, R8RP.3, which was derived from midgestation placentas of PVG.R8 (RT1.Aa) rats, was shown to express class I antigens similarly to those of trophoblast cells in situ. Both unstimulated and IFN-gamma-exposed metabolically labeled R8RP.3 cells synthesized more Pa than RT1.Aa antigen. The reverse was true for labeled spleen cells from PVG.R8 rats. The R8RP.3 cells failed to stimulate allogeneic lymphocyte proliferation even when high levels of both classical and nonclassical class I MHC antigens were expressed on their membranes after incubation with IFN-gamma. These experiments thus supply the first evidence that the inductive phase of the immune response is not promoted by trophoblast cell class I MHC antigens, which could explain the failure of mothers to mount immune responses to class I MHC positive trophoblast cells.