Abstract
Summary
1. Serum was obtained from umbilical cords of healthy newborn babies and from their mothers just after delivery. Liquid preparations of placentas were produced by freezing, thawing, comminution and centrifugation. When tested against 7 species of bacteria, sera and placenta showed bactericidal activity, particularly against Gram negative forms. Placenta and cord serum were active against the same organisms as maternal serum from same patient.
2. Maternal and cord sera and placentas contained lysozyme, complement, and properdin. Placenta and cord serum showed a higher concentration of lysozyme than maternal serum. Placental preparations contained less complement and properdin than serums.
3. Heating at 56°C for 30 minutes caused complete loss of bactericidal activity in placental preparations. Absorption with killed bacteria usually caused loss of bactericidal activity, generally against the absorbing organism only, and this specific bactericidal activity could be restored by addition of heated placenta.
4. Placenta contains antibacterial substances of blood but seems to have little or no detectable bactericidal substance of its own. Apparently it protects the fetus from bacterial infection largely by transmitting protective substances from mother and mechanically impeding access of bacteria to the fetus.
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