Effect of progesterone on human mesenchymal stem cells.

Progesterone is considered to be a major reproductive steroid hormone which supports the successful development of pregnancy. One of the basic targets of progesterone are stromal cells in endometrium which are triggered to undergo decidualization in preparation to accept the embryo. However, the endometrial stroma consists of different subpopulations of cells with varying characteristics and functions as one of the subpopulations are the endometrial mesenchymal stem cells (MSCs) which seem to be located both in the basal layer and in the functional layer of the endometrium. In all cases, these cells have the features of typical MSCs such as adherence and differentiation in multiple cell lineages. The endometrial MSCs are stimulated by progesterone to increase the expression and secretion of immunomodulatory proteins such as HLA-G and PIBF.

Production and characterization of a novel monoclonal antibody against progesterone-induced blocking factor (PIBF).

Progesterone-induced blocking factor (PIBF) has been described as an active factor intimately involved in regulation of the immune response in pregnancy. It has been shown that PIBF biased the cytokine balance to Th2-type in pregnancy and inhibited the activity of NK cells. The biological roles of PIBF would be better defined if methods for its detection and measurement in biological fluids are available. However, so far, reliable antibodies have not been developed to be used as specific probes. A monoclonal antibody designated as MAB 3A6 was produced and characterized. MAB 3A6 reacts specifically with PIBF. It can detect this protein in biological fluids when tested by immunoblot and recognizes PIBF expressed on the surface of lymphocytes of pregnant women stimulated in vitro with progesterone. The characteristics of MAB 3A6 makes it the possible basis for development of a clinically applicable assay to assess the presence and concentration of PIBF in biological samples.

Monoclonal antibody against a cell wall marker protein for embryogenic potential of Dactylis glomerata L. suspension cultures.

We identified and isolated a monoclonal antibody (MAb 3G2) raised against extracellular proteins from microcluster cells of orchard grass (Dactylis glomerata L.) embryogenic suspension culture. MAb 3G2 recognized with high specificity an antigen ionically bound within the primary cell wall and in the culture medium of microcluster cells. Two-dimensional polyacrylamide gel analysis and blotting of proteins on PVDF membrane showed that MAb 3G2 detected a single polypeptide of apparent molecular mass of 48 kDa and an isoelectric point (pI) of 5.2, designated EP48. A transient expression during somatic embryogenesis was observed for EP48. Indirect immunofluorescence showed that this protein highly accumulated in the cell walls of some single cells, microclusters and partly in proembryogenic masses (PEMs), but not in globular embryos of the embryogenic cell line and microclusters from the non-embryogenic cell line. Signal intensity varied between individual cells of the same population and in successive stages of somatic embryo development. Screening of several D. glomerata L. embryogenic and non-embryogenic cell lines with MAb 3G2 indicated the presence of ECP48 in only embryogenic suspension cultures at early stages of embryo development long before morphological changes have taken place and thus it could serve as an early marker for embryogenic potential in D. glomerata L. suspension cultures.