Cytokine-related immunopotentiating activities of paramylon, a beta-(1-->3)-D-glucan from Euglena gracilis.

Paramylon, a beta-(1-->3)-D-glucan, isolated from Euglena gracilis, was tested for its adjuvant activity on the antibody response to sheep red blood cell (SRBC) in mice. Paramylon markedly enhanced anti-SRBC plaque-forming cell production at a dose of 10 mg/kg. It was also found that in vitro addition of lipopolysaccharide in culture to macrophages from paramylon-treated mice produced a large amount of interleukin 1 (IL-1) and there was a significant level of interleukin 6 (IL-6) induced transiently in the blood of these mice. As IL-1 and IL-6 play crucial roles in the immune response to T cell-dependent antigens like SRBC, the immunopotentiating effect of paramylon might be expressed through the action of these cytokines.