Sophorolipids Decrease IgE Production in U266 Cells.

Abstract

RATIONALE: Sophorolipids are promising modulators of the immune response. We have previously demonstrated that sophorolipids decreased sepsis related mortality at 36 hr in vivo in a rat model of septic peritonitis by modulation of nitric oxide, adhesion molecules and cytokine production. In this study we assessed the effect of sophorolipids on IgE production to explore the anti-inflammatory effects of sophorolipid in a cellular model of allergic disease. METHODS: U266 (IgE producing myeloma cell line) were cultured in complete RPMI medium (cRPMI) +/- increasing concentrations of sophorolipids (0.1-10ug/ml) for 3 days after which levels of IgE and soluble CD23 (sCD23) protein were determined in culture supernatants (ELISA); cells were assessed for cell surface expression of CD23 and CD38 and changes in cell morphology compared with controls (cRPMI, 20% sucrose vehicle). Cell viability was determined by Trypan blue exclusion (>95%). Data are reported as mean IgE (IU/ml)+/-SE and significance between groups was determined by student's t-test. RESULTS: U266 cells cultured in cRPMI or sucrose vehicle produced high levels of IgE (520IU+/-32). Addition of sophorolipids maximally decreased IgE production at 1.0ug/ml (416+/-8SE) (p<0.01). Similar numbers of sCD23 and cell surface expression of CD23 were detected among all groups. Addition of increasing sophorolipid concentration (10ug/ml) correlated with a bimodal cell surface expression of CD38 and an increase in the percentages of plasma-like cells compared with controls (14%, 4% respectively)(p<0.05). CONCLUSIONS: Sophorolipids decrease IgE production in U266 cells, possibly through affecting plasma cell activity. This suggests that sophorolipids possess anti-inflammatory activity and may provide a novel therapy in diseases of altered IgE regulation.