Apical membrane antigen 1 domain III and Merozoite surface protein 1 19 kDa fragment fusion protein (PfCP-2.9)

The target is a recombinant fusion protein designed as a blood-stage malaria vaccine candidate, most prominently represented by the PfCP-2.9 construct [1, 3]. It consists of the domain III of the Apical Membrane Antigen 1 (AMA-1) and the 19 kDa C-terminal fragment of Merozoite Surface Protein 1 (MSP1-19) from Plasmodium falciparum [1, 6]. AMA-1 is a microneme protein essential for the reorientation and invasion of the parasite into host erythrocytes, while MSP1-19 is a major surface protein involved in the initial attachment and subsequent invasion steps [3, 9]. By fusing these two domains, the vaccine aims to elicit a synergistic immune response that produces high titers of inhibitory antibodies capable of blocking multiple pathways of parasite entry [2, 10]. This chimeric approach is intended to overcome the high level of genetic polymorphism found in individual antigens like AMA-1 and to enhance the overall immunogenicity and protective efficacy compared to single-antigen vaccines [5, 11]. Clinical and preclinical studies have shown that antibodies induced by this fusion protein can effectively inhibit parasite growth in vitro by preventing the necessary proteolytic processing and host-cell interactions required for infection [4, 9]. The structural integrity of the fusion, particularly its disulfide bond-based conformation, is critical for inducing a protective immune response [1, 4]. This target represents a significant effort in the development of multi-antigen vaccines to combat the complex life cycle and diversity of the malaria parasite [10, 11].

Other names

AMA1-MSP119PfAMA1-MSP119AMA-1(III)/MSP1-19 chimeric proteinChimeric protein 2.9PfCP-2.9

Induction of neutralizing antibodies that block merozoite invasion of erythrocytes by inhibiting the proteolytic processing of MSP1 and the interaction of AMA-1 with the host cell membrane [3, 9, 13].