Effects of caffeine and cortisol on Natural Killer cell function

Natural Killer (NK) cells play a critical role in immune defense against cancerous and infected cells through cytotoxic activity. NK cell activity is often regulated by a variety of signalling molecules, and release of these molecules can be governed by a multitude of compounds and stimulants.

This study investigated specifically the independent and tandem effects of caffeine and cortisol on NK cell function, using an in vitro fluorescence-based cytotoxicity assay. NK cells were exposed in varying concentrations (1-10 uM) of caffeine, cortisol, and combined caffeine-cortisol concentrations in co-culture with target cells for 48 hours.

Cytotoxicity was quantified via relative fluorescence reduction and analyzed. Results indicated that both stimulants independently reduced cytotoxicity across all concentrations tested. Caffeine exposure was relatively consistent, while cortisol exhibited dose-dependent decreases. Combined treatment resulted in lower cytotoxicity overall, but a two-way ANOVA test revealed no statistically significant interaction between the two compounds (p=0.83).

These findings indicate that both stimulant and stress-associated compounds can independently impair NK cell function in vitro, emphasizes the importance of considering multiple stressors when evaluating immune function, and suggest that further research is needed to explore the interactions of the two compounds under different conditions.