The finding of an association between reduced risk of clinical malaria and infection with parasites of merozoite surface protein 1 (MSP-1) type RO33 or MSP-2 type 3D7 further suggests that the concomitant immunity is, at least in part, a consequence of a response to these major merozoite surface proteins.
IgG and IgG3 antibodies to merozoite surface protein-2 (MSP-2) of Plasmodium falciparum have been associated with protection from clinical malaria in independent studies.