Evaluation of poliovirus antibody titers in orally vaccinated semi-captive chimpanzees in Uganda.

Background: To understand immunological responses in chimpanzees vaccinated with live-attenuated vaccine (oral polio vaccine; OPV), serum neutralizing antibodies against poliovirus types 1, 2, and 3 were investigated over time.

Methods: The neutralizing antibody titers against poliovirus types 1, 2, and 3 were determined by microneutralization test using 100 ID(50) of poliovirus types 1, 2, and 3 (Sabin strains).

Results: Neutralizing antibodies against poliovirus types 1, 2, and 3 were detected in 85.7%, 71.4%, and 65% of the serum from 42 chimpanzees tested 9 years post-vaccination. The neutralizing antibody titers in chimpanzees were similar to the documented levels in human studies as an indicator of vaccine efficacy.

Conclusions: This study reveals persistence of neutralizing antibodies in chimpanzees for at least 9 years after vaccination with OPV. This first study in chimpanzees provides useful information for the evaluation of the success of vaccination with OPV in other captive apes.