CORRELATIONS BETWEEN THE INTENSITY OF FMLP-DEPENDENT RESPIRATORY BURST AND CELLULAR FATTY-ACID COMPOSITION IN HUMAN NEUTROPHILS

The peripheral brood neutrophils were isolated from a group of normal subjects and their fatty acid composition determined by capillary gas-chromatography. The superoxide (O-2(-)) release by the same cell preparations in response to formyl-methionyl-leucyl-phenylalanine was also determined following cytochrome c reduction in a microprate assay. A strong negative correlation was found between C18:2 (linoleic acid) (r = -0.703, P = 0.001) and C:16:0 (palmitic acid) (r = -0.569, P = 0.009) and fMLP-stimulated O-2(-) release, whereas C20:4 (arachidonic acid) correlated positively (r = 0.448, P = 0.048). Other fatty acids, namely C12:0, C14:0, C16:1, C18:1, C18:3, C18:4, C20:0, C20:1, C20:2, C20:5, C22:0, C22:1, C22:6, C24:0 and C26:0, were not correlated with O-2(-). No correlations were found between fatty acid composition and O-2(-) release from resting cells and from cells stimulated by phorbol-myristate acetate. These results suggest that the fatty acid composition of blood neutrophils may be a critical factor determining the capability of releasing free radicals in response to formylpeptides. Moreover, since a concomitant increase of arachidonic acid and decrease of its precursor linoleic acid has been found in high-responsive neutrophils, the rate of the enzymes of the arachidonic acid biosynthetic pathway (elongases and desaturases) appear to play an important role.