Abstract
It is a well-known fact that there are discrepancies between titers of the neutralizing antibody in the serum of immunized mice and their protective ability against the intracerebral infection with neurotropic viruses.
In experiments of mice with a fixed strain of the rabies virus, the authors titrated successively the neutralizing antibodies in the serum and the brain tissue and the protective ability against the intracerebral infection following intraperitoneal immunizations with living virus. Antibodies in the brain tissue were measured as follows: mice were thoroughly irrigated with 20ml of 1% citratesaline from the left ventricle of heart after bleeding under ethernarcosis and being cut in the right ventricle of heart. The brain was removed, washed with the saline, and homogenized with broth after weighing. Following centrifugation, the supernatant, after heating at 50°C for 20 minutes, was mixed with the virus suspension, and titrated of its neutralizing property by the intracerebral inoculation to normal mice.
The antibody in the serum was sustained at high titers during 7 weeks after the immunization, whereas that in the brain tissue decreased rather rapidly proportionately to the decrease of protective ability. The seeming parallelism between the latter two factors suggests an important role of the brain tissue antibody in the protection against the intracerebral infection of rabies. virus.
