Measuring Plasma Cytokine and Cortisol Responses

Plasma samples and supernatants from PBMC stimulations were analyzed using commercially available ELISA kits according to the manufacturers' instructions. In detail, plasma samples were analysed for IL-6 (Quantikine HS ELISA; R&D Systems Europe, Wiesbaden, Germany), and cortisol (IBL International, Hamburg, Germany). As TSST-induced changes in plasma cortisol in the original study (8 (link)) were most pronounced between time point 1 (baseline; –5 min) and 3 (+15 min), we used the respective AUC to compare urban participants who grew up with absolutely no animal contact with urban participants who grew up with occasional animal contact (Figure 3) in the present study. Accordingly, we calculated AUC between time point 5 (90 min) and 6 (120 min) for plasma IL-6 levels in the current study to compare urban participants who grew up with absolutely no animal contact with urban participants who grew up with occasional animal contact (Figure 3), as TSST-induced differences between urban and rural participants in plasma IL-6 levels were only detectable at these late stages.