THE STIMULATION AND INHIBITION OF T-CELL PROLIFERATION BY HELICOBACTER-PYLORI COMPONENTS

The purified T cells from peripheral blood of healthy human volunteers , seronegative for anti-Helicobacter pylori antibody were stimulated i n cultures with live or heat-killed H. pylori rods or with bacterial s ialic acid specific surface haemagglutinin (sHA), a crude surface (SF) or cytoplasmic (CF) fractions. It is demonstrated that H. pylori bact eria contain both stimulatory and inhibitory components for T cells of healthy individuals. The sHA as well as SF (5-20 mu g) induced the pr oliferative response of T lymphocytes. By contrast, CF inhibited in do se dependent manner, the proliferation of T cells in the cultures stim ulated with H. pylori bacteria or PHA. The result suggest that in vivo , a dominance of activation or immunosuppression could depend on the c oncentration of the bacteria and their products in infective foci.