Vaccination of Rhesus monkeys (Macaca mulatta) against Plasmodium knowlesi by the use of nonviable antigen.

This study was part of a long-term project with the ultimate goal of developing a malaria vaccine for use in man. Rhesus monkeys that had been vaccinated with a nonviable antigen given in combination with Freund's adjuvant were protected against a normally lethal challenge of Plasmodium knowlesi. Use of the antigen alone or in combination with other adjuvants was not successful. The fact that monkeys were protected against an infection that is normally lethal suggests that a similarly prepared antigen might be of use against malaria in human beings.