Uterine receptivity in the baboon: modulation by chorionic gonadotropin.

Embryonic signals not only rescue the corpus luteum but also modulate the uterine environment in preparation for implantation. Chorionic gonadotropin (CG), an early embryonic signal, is one such molecule. In vivo studies in the baboon show that CG alters the morphology and biochemical activity of the uterus, especially with respect to the three major cell types: luminal epithelium, glandular epithelium, and stromal fibroblasts. Further, CG and progesterone have a synergistic effect on the receptive endometrium. CG action on the endometrial cells is transduced via a seven transmembrane G protein-coupled receptor. Possible signaling pathways involved are discussed.

A comparison of two dissimilar monoclonal antibodies that are directed to a common epitope in the reduced and carboxymethylated chicken riboflavin carrier protein.

Two monoclonal antibodies, D2A1 and D5G3 were elicited by immunization with a preparation of chicken egg riboflavin carrier protein which had been reduced and carboxymethylated. Epitopes recognised by the monoclonal antibodies were mapped using the Pepscan method. Epitopic determinants for D2A1 as well as D5G3 were identified within a region spanning 13 amino acids (residues 170-182) in the primary sequence of riboflavin carrier protein. Interestingly, these monoclonal antibodies, despite sharing a common epitope exhibited a marked difference in their binding to native (folded) riboflavin carrier protein versus reduced carboxymethylated (unfolded) riboflavin carrier protein. Both monoclonal antibodies bound reduced carboxymethylated riboflavin carrier protein to comparable extents in solid phase (ELISA and immunoblots) and liquid phase (radioimmunoassay) assays. However, while D5G3 could bind native riboflavin carrier protein in solid and liquid phase assays, D2A1 showed negligible binding to the native structure. Alanine substituted peptide analogs of the epitope in question defined the crucial amino acids of the epitope needed for binding to the two antibodies.