Effect of exopolysaccharide V2-7, isolated from Halomonas eurihalina, on the proliferation in vitro of human peripheral blood lymphocytes.

The immunomodulatory activity of the exopolysaccharide V2-7, a sulfated pol ymer excreted by the moderately halophilic bacteria Halomonas eurihalina, w as studied in vitro, [H-3]thymidine incorporation and flow-cytometry measur ements showed that this exopolysaccharide enhanced the unspecific prolifera tion of human lymphocytes in response to the presence of anti-CD3 monoclona l antibody. It was effective at concentrations of less than 1 mu g/ml, maxi mum activity being achieved at 0.2 mu g/ml.