Effect of β-Casein on Cytokine Production of Mouse Spleen Lymphocytes

Abstract

We showed β-Casein derived from bovine milk dose-dependently enhanced interferon (IFN)-γ and tumor necrosis factor (TNF)-α productions but not interleukin (IL)-4 production by mouse spleen lymphocytes. Furthermore, β-Casein increased the percentage of CD4⁺ T cell ratio but not CD8⁺ T cell ratio. That is, β-Casein significantly increased CD4⁺/CD8⁺ ratio. It is supposed from these results that β-Casein activates CD4⁺ T cells, especially Th1 type cells. And, the effects of β-Casein on the mRNA expressions of various cytokines in spleen lymphocytes were performed using RT-PCR method. RT-PCR analysis showed that spleen lymphocytes expressed the mRNA for IFN-γ, IL-2, IL-4, IL-6, IL-10 and IL-12p40 under Concanavalin A (ConA) stimulation. In addition, β-Casein stimulus increased the mRNA level of IFN-γ, IL-4 and IL-6 under ConA stimulation. And β-Casein stimulus increased the mRNA level of IL-12p40 under none stimulation. These results suggested that β-Casein activated not only IFN-γ production but also transcription activity of IFN-γ and spleen T cell response to the β-Casein is of the Th1 type. Moreover, the binding of the β-Casein to spleen lymphocytes was assessed by flow cytometory. β-Casein was strongly bound to some spleen lymphocytes, which were expected to be β-Casein sensitive population.