THE ANTIBODY RESPONSE OF RABBITS TO INJECTIONS OF EMULSIONS AND EXTRACTS OF HOMOLOGOUS BRAIN.

Rabbits injected with fresh emulsions of homologous brain developed few or no antibodies capable of fixing complement in the presence of aqueous emulsions or alcoholic extracts of rabbit brain. Complement-fixing antibodies, however, were produced in rabbits by means of injections (1) of sterile emulsions of homologous brain which had been allowed to stand at room temperature for 5 to 30 days and (2) of emulsions of homologous brain experimentally infected with vaccine virus. The antisera that were produced following injections of emulsions of autolyzed homologous brain were shown by absorption tests to contain both specific and non-specific antibodies. The specific brain antigen was found to be approximately six times as abundant in the white matter as in the grey. It was almost absent from the brain of fetal and newly born rabbits, but increased in amount with the age of the animal to reach a maximum concentration at maturity. The specific antigen seemed to parallel the myelin content of brain tissue.