Identification of lactate as a potential inhibitory factor within epithelial cell supernatant and its effects on type 2 T cell populations

Abstract / Short Summary Epithelial cells have been shown previously to inhibit release of type 2 cytokines from T cells and this process could be important in a type 2-mediated diseases such as asthma. Factors secreted by epithelial cells could regulate inflammatory responses and release an ‘all is well’ signal such that the immune system is controlled. Here we show that lung epithelial cells are able to inhibit IL-2 driven type 2 cytokine release by PBMC cells across a transwell indicating the involvement of soluble mediators. We then fractionate the mediators within the conditioned media using methanol chloroform separation and size fractionation. Inhibitory activity was demonstrated within the polar fraction of supernatant separated by methanol chloroform extraction. We then found that lactate, a component within the polar fraction was able to mediate inhibition of the type 2 cytokines. The inhibitory activity of lactate deserves further study and could play a role in the inhibition of T cell derived cytokines in vivo.