Effect of pyridoxal 5′-phosphate on human neutrophil respiratory burst and adhesion on serum coated microplates

The effect of pyridoxal 5′-phosphate (PP) on human polymorphonuclear leukocytes respiratory burst and on cellular adhesion on serum coated microplates was investigated. No dose-response effect was observed after 10 min pre-treatment at 37 °C of human neutrophils with increasing doses of PP, ranging from 0.05 mM/L to 0.5 mM/L. The production of superoxide anion (O2), after challenging cells with 0.5 pM/L formyl-methyonyl-leucyl-phenylalanine, 50 ng/mL phorbol myristate acetate or 50 pg/mL concanavalin A was comparable to that observed by pre-treating cells with phosphate buffered saline only (control, no PP), therefore indicating that PP did not affect neutrophil respiratory burst in our assay conditions. Evaluation of the effect on cellular adhesion onto fetal bovine serum pre-coated microplates produced the same results. As previous results showed that PP in the range of 0.01 mM/L to 0.6 mM/L proved to be an efficient inhibitor of neutrophil aggregation, the evidence reported here might contribute to establish PP as a good in vitro leukocyte anti-aggregant which does not affect other functional parameters.