Publications

Glycodelin is an endometrial protein with proposed immunomodulatory activity during human embryonic nidation. In this review we describe the effects of ovarian hormones on glycodelin transcription, synthesis, and secretion by human epithelial cells and focus on the importance of glycodelin in implantation. We demonstrate that glycodelin transcription, synthesis, and secretion by human epithelial cells are stimulated by progestins and antiprogestins but not by estrogen. Sequences localized within a 403-base-pair region flanking the 5' human glycodelin gene promoter appear to be responsible for transcriptional activation of this gene mediated by progesterone receptor-ligand complexes. Relaxin, purported to enhance glycodelin production in vivo and in prior in vitro studies, had no stimulatory effect on the expression of this gene in vitro in our models.

The integrin alpha(9)beta(1) mediates cell adhesion to tenascin-C and VCAM-1 by binding to sequences distinct from the common integrin-recognition sequence, arginine-glycine-aspartic acid (RGD). A thrombin-cleaved NH(2)-terminal fragment of osteopontin containing the RGD sequence has recently been shown to also be a ligand for alpha(9)beta(1). In this report, we used site-directed mutagenesis and synthetic peptides to identify the alpha(9)beta(1) recognition sequence in osteopontin. alpha(9)-transfected SW480, Chinese hamster ovary, and L-cells adhered to a recombinant NH(2)-terminal osteopontin fragment in which the RGD site was mutated to RAA (nOPN-RAA). Adhesion was completely inhibited by anti-alpha(9) monoclonal antibody Y9A2, indicating the presence of a non-RGD alpha(9)beta(1) recognition sequence within this fragment. Alanine substitution mutagenesis of 13 additional conserved negatively charged amino acid residues in this fragment had no effect on alpha(9)beta(1)-mediated adhesion, but adhesion was dramatically inhibited by either alanine substitution or deletion of tyrosine 165. A synthetic peptide, SVVYGLR, corresponding to the sequence surrounding Tyr(165), blocked alpha(9)beta(1)-mediated adhesion to nOPN-RAA and exposed a ligand-binding-dependent epitope on the integrin beta(1) subunit on alpha(9)-transfected, but not on mock-transfected cells. These results demonstrate that the linear sequence SVVYGLR directly binds to alpha(9)beta(1) and is responsible for alpha(9)beta(1)-mediated cell adhesion to the NH(2)-terminal fragment of osteopontin.

CD134 (OX40) is a member of the TNF receptor family that is expressed on activated T lymphocytes. T cells from mice that lack expression of CD134 made strong responses to a range of challenges, but they showed impaired proliferation in response to direct stimulation through the TCR with monoclonal anti-CD3epsilon Ab. CD134-deficient mice controlled infection with Leishmania major, Nippostrongylus brasiliensis, and Theiler's murine encephalomyelitis virus, and they made overtly normal Ab responses to a variety of antigens. Thus, CD134 is not essential for many T cell responses in vivo, nor is it required for the provision of help to B cells. Nonetheless, a subtle role in the regulation of T cell reactivity is suggested by the effect of CD134 deficiency on in vitro T cell responses.