Human Leptin Hormone Affects TNF-α Production in Mucosal-associated Invariant T Cells

Background and Aims: Mucosal-associated invariant T (MAIT) cells are striking lymphocyte population in the blood and their importance in immune responses is growing fast. The current study was conducted to evaluate leptin hormone effects on MAIT cell functions. Materials and Methods: Five healthy male donors in ages of ۲۲-۳۰ years were selected and peripheral blood mononuclear cells (PBMCs) were enriched by Ficoll-density gradient. The cells were stimulated by different doses of human recombinant leptin. Using anti-CD۳, anti-CD۱۶۱ and anti-Vα۷. ۲ antibodies, positive CD۳/CD۱۶۱/ Vα۷.۲ MAIT cells were selected among stimulated PBMCS and proliferation alterations (after ۵ days) and intercellular tumor necrosis factor (TNF)-α production (after ۲۴ hours) were determined by flow cytometer. Results: Stimulation of MAIT cells in doses of under ۸۰۰ ng/ml of leptin did not alter the frequency of the cells significantly. However, in ۸۰۰ ng/ml of leptin the number of the cells declined substantially, but statically analysis did show a significant difference with unstimulated and other leptin concentrations (p=۰.۱۲). When the frequency of  intracellular TNF-α positive MAIT cells investigated, it revealed that in doses of ۲۵۰ and ۴۰۰ ng/ml of leptin, the number of the TNF-α. positive cells significantly increased compared to other concentrations (p=۰.۰۰۲). In high concentration of leptin (۸۰۰ ng/ml), the frequency of positive TNF-α cell decreased compared to ۴۰۰ ng/ml of the hormone. Conclusions: Leptin hormone in doses of ۲۵۰ and ۴۰۰ ng/ml has affected MAIT cells’ ability to produce TNF-α cytokine. Therefore, in adipose tissue leptin might be considered as a new source of inflammatory cytokines.

Keywords:

Leptin , MAIT Cells , TNF-α , لپتین , میت سلول ها , TNF-α