Leukocyte adhesion molecule expression during intense resistance exercise

We hypothesized that expression of L-selectin and very late antigen-4 (VLA-4) integrin adhesion molecules would influence cell type-specific redistribution during exercise. Women subjects performed six sets of 10-repetition maximum squats. L-selectin and VLA-4 integrin were measured by using flow cytometry pre- and postexercise on peripheral blood neutrophils and lymphocytes (n = 29 subjects) and lymphocyte subsets (n = 70 subjects), respectively. Neutrophil concentration increased 41.8% (P < 0.001), whereas the percent expressing L-selectin was unchanged (79%). Lymphocyte concentration increased 61.8% (P < 0.001). The percent of T cells expressing L-selectin decreased from 73.5 +/- 8.9 to 68.2 +/- 11.4% (P < 0.001); the combined population of natural killer and B cells expressing L-selectin decreased from 80.4 +/- 22.5 to 62.7 +/- 25.8% (P < 0.001). VLA-4 integrin was expressed by nearly all lymphocytes both pre- and postexercise. The proportional decrease in L-selectin positive cells could have resulted from 1) shedding of L-selectin, 2) selective entry of L-selectin-negative subsets, or 3) selective removal of L-selectin-positive subsets.