Different abilities of two distinct Fcγ receptors on guinea pig polymorphonuclear leukocytes to trigger the arachidonic acid metabolic cascade

Abstract

The nature of signals transmitted by two Fcγ receptors (Fcγ₂R for IgG2 and Fcγ₁/γ₂R for both IgG2 and IgG1) on guinea pig polymorphonuclear leukocytes was investigated. The specific binding of hen ovalbumin (OA)‐complexed IgG1 antibody to Fcγ₁/γ₂R did not seem to trigger the release of [³H]arachidonic acid from the cells prelabeled with [³H]arachidonic acid. In contrast, marked release occurred on the binding of OA‐complexed IgG2 antibody to the cells. This reaction was not inhibited, but rather enhanced, by the Fab′ of a monoclonal antibody to Fcγ/γ₂R. Therefore, a signal for the activation of the arachidonic acid metabolic cascade was found to be transmitted by Fcγ₂R, but scarcely by Fcγ₁/γ₂R.