Apical membrane antigen 1 (AMA1) - FVO allele (AMA1)

Apical membrane antigen 1 (AMA1) is an 83 kDa type I transmembrane protein located in the micronemes of Plasmodium falciparum merozoites and is essential for the invasion of human erythrocytes [1.5.1]. During the invasion process, AMA1 is translocated to the parasite surface where it interacts with rhoptry neck protein 2 (RON2) to form a tight junction, a critical step for parasite entry into the host cell [1.2.4, 1.4.2]. The FVO allele represents one of the major divergent variants of AMA1, and its inclusion in multi-allele vaccine candidates like AMA1-C1 and ChAd63-MVA AMA1 is intended to broaden the protective immune response against diverse parasite populations [1.1.1, 1.1.2]. These vaccines aim to elicit high titers of growth-inhibitory antibodies that disrupt the AMA1-RON2 complex, thereby neutralizing the parasite before it can establish an intracellular infection [1.3.4, 1.3.5]. However, the extreme allelic diversity of AMA1 remains a significant therapeutic challenge, as antibodies often exhibit strain-specific efficacy, potentially allowing parasites with different haplotypes to escape the vaccine-induced immune response [1.2.1, 1.3.3]. Clinical development continues to focus on multi-valent formulations and novel adjuvants to overcome this polymorphism and achieve durable, cross-strain protection [1.1.3, 1.3.1].

Other names

PfAMA1AMA-1Apical membrane antigen 1FVO strain AMA1Plasmodium falciparum apical membrane antigen 1

Vaccine-induced antibodies or peptide inhibitors block the interaction between AMA1 and rhoptry neck protein 2 (RON2), preventing the formation of the moving junction and subsequent entry of the parasite into the host erythrocyte.