The functional role of 55- and 75-kDa tumour necrosis factor receptors in human polymorphonuclear cells in vitro.

ABSTRACT

The expression and biological role of 55- and 75-kDa tumour necrosis factor-receptors (TNF-RI and TNF-RII) in human polymorphonuclear cells (PMN) in vitro were studied using agonistic rabbit polyclonal anti-TNF-R antibodies. PMN express TNF-RII predominantly, and release the superoxide anion on stimulation by human recombinant lymphotoxin (LT) in vitro. Anti-TNF-RI but not anti-TNF-RII antibody stimulated the superoxide release mimicking LT. Release of the elastase from azurophilic granule of PMN was augmented by LT in vitro. Anti-TNF-RI but not anti-TNF-RII antibody augmented the elastase release. Release of the lactoferrin from the specific granules of PMN was enhanced by LT in vitro. Anti-TNF-RI but not anti-TNF-RII antibody augmented the elastase release. Release of the lactoferrin from the specific granules of PMN was enhanced by LT in vitro. Anti-TNF-RI but not anti-TNF-RII antibody enhanced the lactoferrin release. These antibodies failed to co-stimulate these PMN functions. The adhesiveness of PMN to a plastic plate and the expression of Mac-1 on PMN were upregulated by LT in vitro. Anti-TNF-RI but not anti-TNF-RII antibody upregulated the adhesiveness and Mac-1 expression of PMN mimicking LT. Though anti-TNF-RII antibody by itself did not alter the adhesiveness and marginally suppressed Mac-1 expression, it maintained the adhesiveness and adhesion molecule expression in the presence of anti-TNF-RI antibody. In summary, PMN predominantly express TNF-RII, the signalling of LT (and TNF) in PMN is mediated mainly by TNF-RI, and the adhesion function can be modulated also by TNF-RII when TNF-RI is stimulated.