Boronate-containing polymer as novel mitogen for lymphocytes.

A novel water-soluble polymer (poly(AAm-co-PBA)) was synthesized by radical copolymerization of 3-acrylamidophenylboronic acid with acrylamide and evaluated as synthetic mitogen of lymphocytes. Boronic acid was introduced in the polymer as recognition site of sugar residues existing on the plasma membrane surface of lymphocyte, since it makes a covalent bonding with polyol compounds including sugars. Obvious increase in [3H]thymidine incorporation of lymphocytes was observed when murine spleen lymphocytes were cultured with poly(AAm-co-PBA), while little proliferative response of lymphocytes was observed in the presence of the homopolymer of acrylamide, the polymer without boronic acid moiety. This suggests that proliferation of lymphocytes was induced through the binding of phenylboronic acid moiety in poly(AAm-co-PBA) with glycoproteins existing on the plasma membrane surface of lymphocytes. Further, poly(AAm-co-PBA) was found to induce even the proliferation of B cell-depleted population of lymphocytes, suggesting T cell stimulation by this boronate-containing polymer.