RH5.1 + RH5.2-VLP + Matrix-M

RH5.1 + RH5.2-VLP + Matrix-M is an investigational combination malaria vaccine targeting the blood-stage of Plasmodium falciparum infection. The vaccine includes two antigens—RH5.1 (a full-length soluble recombinant reticulocyte-binding protein homolog 5) and RH5.2-VLP (a thermostabilized, truncated alpha-helical core of PfRH5 conjugated to hepatitis B surface antigen virus-like particles using SpyTag-SpyCatcher technology)—formulated with the saponin-based adjuvant Matrix-M to enhance immunogenicity[1][2][7]. Both antigens are designed to induce potent antibody responses that inhibit erythrocyte invasion by P. falciparum merozoites, a critical step in malaria pathogenesis[1][2]. The combination aims to maximize both the quantity and quality of functional antibodies by presenting conserved epitopes in different formats (soluble protein and VLP), potentially improving efficacy over single-antigen vaccines[1][2]. Matrix-M acts as an immune-stimulating complex adjuvant composed of saponins from Quillaja saponaria, cholesterol, and phospholipids; it enhances both humoral and cellular immune responses[6][8][9].