Sulfasalazine inhibition of binding of N-formyl-methionyl-leucyl-phenylalanine (FMLP) to its receptor on human neutrophils.

Sulfasalazine, a drug useful in the therapy of inflammatory bowel disease, was found to block N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced arthritis in rabbits as well as FMLP-induced superoxide production and chemotaxis in human neutrophils in vitro. Sulfasalazine was also found to block FMLP binding to human neutrophils with an I50 of 10 microM. The dose-response curve for the inhibition of binding was very similar to the dose-response curves for the inhibition of FMLP-induced neutrophil activation.