PURIFICATION AND CHARACTERIZATION OF A PREGNANCY-ASSOCIATED PROTEIN -TJ6S

PROBLEM: Characterization of the soluble form of a novel protein, TJ6 (TJ6s) with immune suppressive activity from murine fetoplacental unit s. METHOD: Preferential ammonium sulfate precipitation, gel filtration and ion-exchange chromatography were employed to purify the protein T J6s from murine fetoplacental units using an anti-peptide antibody as a detection tool. Biological activity of the purified protein was stud ied in lymphocyte proliferation assays. RESULTS: Purified TJ6s has a M r of approximately 18 kDa as evidenced by SDS-PAGE in both reducing an d non reducing conditions. It exerted a strong anti-proliferative acti vity in both anti-CD3 and Con A proliferation lymphocyte proliferation assays but not in a PHA assay, suggesting that the anti-proliferative effects on T cells are exerted only on cells specifically activated d irectly through T cell receptor complex. CONCLUSION: The results indic ate that TJ6s is a novel anti-proliferative protein that has many of t he characteristics that are considered necessary for survival of the f etal allograft.