Reactogenicity of a malaria merozoite antigen in Aotus monkeys compared with the effects caused by two new adjuvants, CP-20,961 and [B30]-MDP.

Six Aotus trivirgatus monkeys were included in a clinical study to compare the adverse reactions caused by a Plasmodium falciparum antigen and 2 adjuvants, a lipoidal amine, CP-20,961, and a muramyl dipeptide derivative, [B30]-MDP. Two monkeys were given 2 intramuscular injections, 3 weeks apart, of 1 of these vaccine components. Both the antigen and the two adjuvants caused local and general reactions as well as hematological and biochemical changes. Except for an up to 60% rise in leukocyte count, the antigen caused reactions least, followed by [B30]-MDP. CP-20,961 evoked more vigorous reactions and changes, but none of them reached such an extent that it would contraindicate its potential use in forthcoming vaccine studies. We conclude that both adjuvants are to be considered as relatively safe when combined with an appropriate P. falciparum antigen.