Acquired immunity to Plasmodium berghei yoelii in mice

Abstract

Acquired immunity to malaria was investigated in mice which had recovered from a primary infection with P. b. yoelii. It was found that antibody synthesis and protection persisted at least 17 months, although both decreased somewhat during this interval. Strong cross-protection was exhibited against a virulent isolate of the parent strain but not against the type species, P. b. berghei. It was not possible to detect persisting antigen or persisting infectious organisms in immune mice; both blood-induced and sporozoite-induced infections were followed from this standpoint.