Leukocyte adhesion molecule expression during intense resistance exercise

We hypothesized that expression of L-selectinand very late antigen-4 (VLA-4) integrin adhesionmolecules would influence cell type-specific redistribution duringexercise. Women subjects performed six sets of 10-repetition maximumsquats. L-selectin and VLA-4 integrin were measured by using flowcytometry pre- and postexercise on peripheral blood neutrophils andlymphocytes (n = 29 subjects) andlymphocyte subsets (n = 70 subjects),respectively. Neutrophil concentration increased 41.8%(P < 0.001), whereas the percentexpressing L-selectin was unchanged (79%). Lymphocyte concentrationincreased 61.8% (P < 0.001). Thepercent 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- andpostexercise. The proportional decrease in L-selectin positive cellscould have resulted from 1) sheddingof L-selectin, 2) selective entry ofL-selectin-negative subsets, or 3)selective removal of L-selectin-positive subsets.