Antibody responses in the cerebrospinal fulid of cynomolgus monkeys after intracerebral inoculation with paramyxoviruses.

Cynomolgus monkeys with or without measles antibody were intracerebrally inoculated with measles or canine distemper viruses, and antibody responses in the cerebrospinal fluid (CSF) were investigated. In measles antibody-free monkeys, natural infection with wild measles virus or intracerebral inoculations with two attenuated measles vaccines evoked primary antibody responses to measles virus in the sera but not in the CSF. In measles-immune monkeys, intracerebral inoculation with the TYCSA strain of measles virus produced a significantly high titer of measles antibody in the CSF with a minimal rise in the serum antibody and resulted in a significant decrease in serum/CSF antibody ratios. Intracerebral inoculation of a neurotropic canine distemper virus, the Onderstepoort strain, into measles-immune monkeys caused production of both measles and distemper antibodies in the CSF. Inoculation of measles-immune monkeys intravenously with measles virus or intracerebrally with rubella virus, which has no antigenic relation to measles virus, failed to evoke a measles antibody response in the CSF. These results indicated that local production of measles antibody in the CSF was caused by a stimulus within the central nervous system of measles virus antigen or canine distemper virus antigen that partially cross-reacted with measles virus antigen as a secondary antibody response.