Th1 and Th2 lymphocytes roll on HA-coated coverslips via CD44. Rolling on HA-coated coverslips by naive (A), Th1 (B), and Th2 (C) lymphocytes. Adhesion on HA-coated coverslips by naive (D), Th1 (E), and Th2 (F) lymphocytes. Preincubation of cells with a blocking Ab to CD44 prevents both rolling and adhesion. Data are expressed as the arithmetic means ± SEM of at least 3 separate experiments. *P < .05 relative to PBS-coated plates; #P < .05 relative to Th1 adhesion to HA.