Immunofluorescent Staining: BALB/c mesenteric lymph node cells were stained with either Rat IgG2c-FITC (as a Negative Control) or Rat anti-Mouse CD90-FITC. Lymphocytes were then gated and analyzed on a FACScan (TM) flow cytometer (BDIS, San Jose, CA). Amount Used: 1 ug/10e6 cells.