Platelet-activating factor and eicosanoids are mediators of local and systemic changes induced by immune-complexes in mice

Abstract

A passive Arthus reaction (AR) induced in the peritoneal cavity of mice was followed by increased local vascular permeability and haemoconcentration. The intensity of the increased vasopermeability was higher in BALB/c compared with C3H/HePas mice despite the latter being 10 times more sensitive to platelet-activating factor (PAF). C3H/HePas mice however, exhibited higher levels of haemoconcentration and shock-like symptoms. Both events were inhibited by the PAF antagonist, WEB 2170. Indomethacin reduced both pathological events whereas L663,536, that inhibits leukotrienes synthesis reduced haemoconcentration but only in BALB/c mice. PAF was released into the peritoneal cavity, peak release being at 10 min after induction of AR. Prostaglandin E 2 (PGE 2), thromboxane B 2 (TXB 2), leukotriene B 4 (LTB 4),and leukotriene C 4/D 4 (LTC 4/D 4) were also released at this time. Similar levels of PAF and eicosanoids were found in BALB/c and C3H/HePas mice except for LTB 4, which was higher in C3H/HePas. It is concluded that PAF and eicosanoids are mediators of local and systemic changes induced by immune complexes in the peritoneal cavity of mice.