Capsicum extract and its constituents modulated the production of immunoglobulins in Peyer's patch cells ex vivo

We investigated the influence of red chili peppers (Capsicum annuum Lin.) on intestinal B cell-dependent immune responses. Production of two isotype immunoglobulins, immunoglobulin-A and G1 (IgA and IgG1, respectively) was measured in Peyer's patch (PP) cells after treatment with Capsicum extract, capsaicin, or carotenoids. PP cells isolated from mice that had been orally injected with Capsicum extract or capsaicin (Capsicum's main bioactive pungent compound) secreted significant amounts of IgA and IgG1, irrespective of lipopolysaccharide-stimulation. In contrast, oral injection of β-carotene, β-cryptoxanthin or capsanthin (the free forms of carotenoids found in Capsicum) significantly reduced the production of antibodies. Flow cytometric analysis revealed that Capsicum and capsaicin caused a small increase in the number of CD19+ B cells and a decrease in CD3+ T cells in PP, while carotenoids did not affect either population. These results indicate that Capsicum extract or capsaicin potentiated intestinal humoral immune responses via antibody secretion.