B cells secrete GABA, which provokes a pro-tumor immune microenvironment.

In a recent publication in Nature, Zhang et al. report that foreign antigen stimulation elicits bountiful changes in lymphatic metabolite production-changes that include B cells secreting GABA, which reprograms macrophages and limits T cell cytotoxicity. This signifies a new mechanism by which B cells regulate immune suppression and facilitate tumor progression.