Mitogenic Activity of Bacterial Fractions in Lymphocyte Cultures

Abstract

Summary: Purified fractions of tuberculin prepared by Seibert were tested for the ability to cause blast-cell transformation in cultures of peripheral blood leukocytes from normal donors and from patients with tuberculosis, sarcoidosis and myocarditis. The fractions tested included a purified protein derivative of tuberculin (PPD-S), polysaccharide I which contained 12.8% of protein, and polysaccharide II which contained a trace of protein. PPD-S caused transformation of lymphocytes from healthy Mantoux-positive individuals. Polysaccharide I caused a low but significant rate of lymphocyte transformation in approximately one third of tests employing leukocytes from Mantoux-positive donors. Polysaccharide II did not stimulate blast-cell transformation in any instance. The mitogenic activity of the purified fractions was directly proportional to the amount of biologically active protein present. The partial or complete failure of purified polysaccharides I and II respectively to stimulate blast transformation in cultured leukocytes from tuberculin-sensitive individuals was consistent with the apparent inability of some polysaccharide antigens to evoke a characteristic anamnestic response.