The mitogenicity of dextrans for B lymphocytes in man

Abstract

Branched dextran B1355 (57% α1–6, 35% α1–3, and 8% α1–2 α1–4 linkages) induced in vitro stimulation of human peripheral blood and spleen lymphocytes. However, linear dextran B512 (96% α1–6 and 4% α1–3 linkages) and its depolymerised fractions irrespective of molecular weight (from 1 × 10 4 – 2 × 10 6) were not mitogenic for human lymphocytes from spleen or peripheral blood. This difference in response was not due to the mitogenicity of the α1–3 epitope, as α1–3 glucan itself was not stimulatory. The incidence and magnitude of the response to dextran B1355 were increased in patients with gingival or periodontal disease compared with subjects with clinically healthy gingiva. B-cell mitogens stimulate human peripheral blood lymphocytes from control subjects in the following order of effectiveness: dextran sulphate (100% responders), levan (87% responders), and dextran B1355 (62% responders).