Purified B cells induce CD4 T cell activation in CL patients. B cells and CD4 T cells were purified from PBMCs of CL patients (n = 10), incubated for 5 days separately or together, with or without promastigote L. panamensis antigen (pLAg), and stained for CD4, CD25, CD127, and CD69. A. Representative plots for each culture condition showing the expression of CD25, CD127 and CD69 in the CD4+ gate. B. Expression of CD25 within the CD4+ gate. C. Expression of CD69 within the CD4+ gate. D. Percentage of CD25hiCD127- cells within the CD4+ gate. *p < 0.05, **p < 0.01, ***p < 0.001.