N-formyl-methionyl-leucyl-phenylalanine (FMLP) inhibits both the interferon-g and interleukin-10 induced expression of FcgRI on human monocytes.

BEIGIER-BOMPADRE, MACARENA; BARRIONUEVO, PAULA; ALVES-ROSA, FERNANDA; RUBEL, CAROLINA; PALERMO, MARINA; ISTURIZ, MARTÍN

Estocolmo, Suecia.

Congreso; 11th International Congress of Immunology.; 2001

FcgRI is a high affinity receptor capable of inducing functions that include phagocytosis, antibody-dependent cell-mediated cytotoxicity (ADCC) and secretion of cytokines. We investigated the effect of FMLP on the overexpression of FcgRI induced by both IFN-g and IL-10 on human monocytes. We demonstrate that FMLP 10-6 M significantly abrogated IFN-g and IL-10-induced FcgRI expression evaluated by flow cytometry, although its basal expression was not altered. However, other IFN-g mediated effects such as the overexpression of the MHC class II antigens and the enhancement of LPS-induced secretion of TNF-a were not affected by FMLP treatment. The formyl peptide completely inhibited the IFN-g and IL-10-induced enhancement of ADCC and phagocytosis carried out by adherent cells. The inhibitory effect of FMLP on FcgRI upregulation could exert an important regulatory effect during the evolution of bacterial infections.