Status of previous and current MSP 1 and MSP 2 of malaria parasites as vaccine targets

Malaria immunity is complex, being species and stage-specific, and requires both innate and adaptive immune responses to protect against a blood-stage Plasmodium parasite. Repeated infections are necessary to generate and maintain clinically protective immune responses throughout a person's lifetime. While repeated natural infections with Plasmodium sp. parasites induce protection from severe disease, they do not confer sterile immunity, making immunity to Plasmodium incomplete. The development of a malaria vaccine is crucial to prevent infection, reduce disease/parasite burden, or prevent the spread of infection from existing hosts, depending on the stage of the malaria parasite life cycle to be targeted. Merozoite surface protein-1 (MSP-1) and merozoite surface protein-2 (MSP-2) are two proteins that pose a challenge to the human immune system and are important candidates for blood-stage malaria vaccine production. Antibodies to MSP-1 can inhibit parasite growth in vitro and have been associated with protection against malaria in several epidemiological studies. MSP-1 elicits not only neutralizing but also opsonizing antibodies against Plasmodium falciparum blood-stage parasites. The induction of opsonizing antibodies might be a crucial effector mechanism for MSP-1-based malaria vaccines. Evidence has shown that antiparasite immune responses can efficiently control malaria parasite infection at all stages, and the induction of host immune responses targeting all stages of the parasite is critical for the development of an effective vaccine. Overall, the immune response to malaria is a dynamic and multifaceted process, and ongoing research is focused on harnessing this knowledge to develop an effective malaria vaccine.