Anti-inflammatory factors in sponge-induced exudate in the rat.

Sterile polyester sponge-induced exudates in the rat have been investigated for high molecular weight substances with anti-inflammatory activity against carrageenan-induced oedema in the rat. The only substances found with this activity were dialysable molecules. Crude but sterile protein fractions isolated from exudate stabilized guinea-pig macrophages at low concentrations. The proteins present in exudates appeared to be identical to normal rat plasma proteins. It is concluded that anti-inflammatory activity associated with high molecular substances in exudate may have been due to bacterial contamination.