Relationship between oxidative burst activity and CD11b expression in neutrophils and monocytes from healthy individuals: Effects of race and gender

Oxidative burst activity and the expression of adhesion molecules have been used as indicators of leukocyte activation status. The aim of the study wa s to delineate the relationship of oxidative burst activity and the express ion of adhesion molecules in neutrophils and monocytes from a pool of healt hy volunteers (n = 96). We also tested the potential role of gender and a r acial background in the individual response differences. Basal and phorbol myristate acetate (PMA)-stimulated oxidative burst and CD11b expression wer e determined using dihydrorhodamine 123 and phycoerythrin (PE)-conjugated a nti-CD11b monoclonal antibodies. PMA markedly increased CD11b expression an d cellular oxidant content in neutrophils and monocytes in all samples. How ever, the responses showed considerable variability among individuals. A po sitive correlation was observed between the responsiveness of neutrophils a nd monocytes in their basal or PMA-stimulated CD11b expressions and PMA-sti mulated oxidative burst activities. In contrast, no correlation was found b etween the level of adhesion molecule expression and cellular oxidant conte nt in monocytes or neutrophils either under basal or under PMA-stimulated c onditions. The reactivity of oxidative burst (i.e., PMA-stimulated over bas al) was significantly lower in neutrophils from African American males comp ared with cells from African American females, white females, or white male s. In contrast, reactivity of monocytes was significantly elevated in white males compared with all other groups. These findings indicate that leukocy tes with a relatively high degree of adhesion molecule expression may displ ay an average or decreased oxidative burst activity, and vice versa. Our fi ndings also indicate that ethnic background may influence the oxidative bur st activity in neutrophils and monocytes. This needs consideration in clini cal studies utilizing healthy volunteers with mixed gender and ethnic backg rounds. (C) 2000 Wiley-Liss, Inc.