2010 年 56 巻 3 号 p. 304-309
Under immunocompromised conditions such as aging, cancer, diabetes, burns, and sepsis, external agents may be useful for upregulation of the immune system to prevent infection. Dietary products have the advantage of being safe and easy to take. An extract of red bell pepper (Capsicum annuum L.) flesh markedly enhanced immunoglobulin M (IgM) production by murine B cells and their proliferation. The effect of the extract on IgM production was not abrogated by treatment with polymyxin B and was also observed in spleen cells of lipopolysaccharide-unresponsive C3H/HeJ mice. Treatment of B cells with the extract resulted in an increase in the number of IgM-secreting cells and cluster of differentiation (CD)138-positive cells. The IgM production-enhancing activity was resistant to trypsin treatment but was heat-labile. The activity was eluted in a peak with a molecular weight of 6000 on gel filtration. These results demonstrated that the extract of red bell pepper enhanced IgM production in B cells and suggest that the active substance(s) in the extract is a non-proteinous heat-labile macromolecule.