Effect of caffeine on antigen-specific immune responses of mouse splenocytes

Caffeine, a natural component of coffee and tea, is one of the most widely consumed drugs in the world. Caffeine can interact with several cell-surface receptors (e.g., adenosine receptors) and can modulate various cellular functions by binding to these receptors. However, there are few reports on its immunological functions. Therefore, we investigated the effects of caffeine on in vitro antigen-specific immune responses of unsensitized (naive) immune cells from transgenic mice expressing the ovalbumin-specific T-cell receptor (TCR). Caffeine treatment significantly suppressed the proliferation of splenocytes and the secretion of interleukin (IL)-2, IL-4, and IL-10 elicited by ovalbumin stimulation. Moreover, immunoglobulin (Ig) G1 secretion was downregulated. In contrast, antigen-specific secretion of IL-12p40, IL-5, IgG2a, and IgA were not affected. These results suggest that caffeine treatment alters antigen-specific immune responses of primary naive immune cells.