Effect of human cord and postoperative serum on experimental inflammation in the rat.

Human cord and postoperative serum depressed the oedema provoked by mediators of the inflammatory reaction such as bradykinin, histamine, serotonin and prostaglandin E2 and also the experimental inflammation caused by carrageenin. Normal human and pregnancy serum did not have such an effect. In two cases of open neural tube defect, one of anencephaly and another of spina bifida, human amniotic fluid also had a strongly depressing effect on the experimental oedema provoked by serotonin. Human amniotic fluid from normal pregnancies did not inhibit this experimental inflammation. A protein-fraction of mol. wt 30,000--100,000 has been isolated from the inhibiting sera and shows the anti-inflammatory activity to be dose-related towards all the oedema-provoking substances used. Immunological studies showed that the inhibiting factor could be a protein in the pre-albuminic region, while alpha-foetoprotein did not appear to be responsible for the anti-inflammatory activity. Our conclusion is that human serum contains a protein of foetal origin with an acute-phase character and strong anti-inflammatory activities analogous to rat alpha 2-macrofoetoprotein.