Cells from BALB/c mesenteric lymph nodes were double-stained with Cd8a monoclonal antibody, clone 53-6.7 (FITC) (Cat # MAB6105) and Cd4 monoclonal antibody, clone GK1.5-PE, gated on small lymphocytes and analyzed on a FACScan™ flow cytometer (BDIS, San Jose, CA)