Immunostimulatory Effects of ß-glucan Purified from Paenibacillus polymyxa JB115 on Mouse Splenocytes.

ABSTRACT

We investigated the effects of ß-glucan purified from Paenibacillus polymyxa JB115 on the viability and proliferation of splenocytes. Splenocytes play a critical role in host immunity. MTT assays and trypan blue exclusion tests revealed that ß-glucan significantly promoted the viability and proliferation of splenocytes over a range of concentrations. However, there was no specific subset change. ß-glucan protected splenocytes from cytokine withdrawal-induced spontaneous cell death. For further mechanistic studies, ELISA assay revealed that ß-glucan enhanced the expression of anti-apoptotic molecules and interleukin 7 (IL-7), a cytokine critical for lymphocyte survival. We also investigated the IL-2 dependency of ß-glucan-treated splenocytes to determine if treated cells could still undergo clonal expansion. In flow cytometric analysis, ß-glucan induced increased levels of the activation marker CD25 on the surface of splenocytes and ß-glucan-treated splenocytes showed higher proliferation rates in response to IL-2 treatment. This study demonstrates that ß-glucan can enhance the survival of splenocytes and provides valuable information to broaden the use of ß-glucan in research fields.