Figure 3.

Fas/FasL expression, release, and apoptosis in PBMCs restimulated with live L. major. PBMCs were restimulated 1:1 with L. major promastigotes for 5 days. Fas expression and levels of apoptosis were assessed using fluorescence-activated cell sorting. White boxes: Unstimulated cultures. Gray boxes: L. major-stimulated cultures. The horizontal and vertical lines in each box represent the median and the range (95% confidence interval), respectively. Differences were calculated by the signed or unsigned Mann-Whitney test. a: Fas expression on PBMCs after L. major restimulation. In CL (n = 12), PBMCs stimulated with L. major up-regulate Fas compared to healthy controls (n = 12) and unstimulated PBMCs. b: Levels of apoptotic cells in L. major-stimulated PBMCs. Apoptosis was assessed using Annexin V/propidium iodide stainings and Annexin V-positive, propidium iodide-negative cells were designated as apoptotic cells. In CL PBMCs stimulated with L. major (n = 13), more apoptosis was measured compared to control PBMCs (n = 12). c: The origin of sFasL was assessed in one donor. Intracellular staining of Fas revealed 2% FasL-expressing cells in L. major-stimulated CL PBMCs. All FasL⁺ cells were T cells, both CD8⁺ and CD4⁺. d: sFasL is secreted by L. major-stimulated CL PBMCs. Levels of sFasL were assessed using enzyme-linked immunosorbent assay. In CL PBMCs (n = 12) stimulated with L. major, there was a significant increase in the levels of sFasL compared to unstimulated cultures or L. major-stimulated control CL (n = 6, P < 0.01).