Caffeine downregulates antibody production in a mouse model

Caffeine is a secondary plant metabolite found in coffee and tea. Its major pathway is interaction with adenosine receptors. Minor pathways are also known. An effect of caffeine on immunity has been proposed. In this paper, the role of caffeine on the immune system was studied, using a BALB/c mouse model. The animals received saline (controls), keyhole limpet hemocyanin (KLH) 1 mg/kg or caffeine (alone or in combination with KLH) in doses of 1–16 mg/kg. The mice were sacrificed 1–7 days later and plasma levels of interleukin (IL) 2, 4, 6, 10, 12 and antibodies against KLH were determined by enzyme linked immunosorbent assay (ELISA). Caffeine caused a significant decrease in KLH-stimulated antibody production. The effect was dose dependent. There were similar findings for IL-2 and IL-4 but not for IL-6, IL-10 and IL-12. The significance of the findings is discussed with extrapolation to humans based on caffeine doses used in the study and the amount of caffeine in available beverages.