MSP3-LSP with aluminum hydroxide

MSP3-LSP/AlOH is a malaria vaccine candidate that combines a long synthetic peptide derived from the conserved region of Plasmodium falciparum merozoite surface protein 3 (MSP3-LSP) with aluminum hydroxide (AlOH) as an adjuvant[2][3][5]. This vaccine has been tested in clinical trials for its potential to protect against malaria, particularly in Africa[10]. ## Composition and Mechanism The vaccine consists of a 95-amino acid long synthetic peptide from the C-terminal conserved region of MSP3, which is a key target for protective antibodies[2][3]. When formulated with aluminum hydroxide, the peptide adsorbs to the adjuvant (99% adsorption as measured by high-performance liquid chromatography)[6]. MSP3-LSP works by inducing a strong cytophilic antibody response, particularly of the IgG1 subclass, which is involved in antibody-dependent, monocyte-mediated protective mechanisms against Plasmodium falciparum[6]. The vaccine targets the blood stage of malaria infection. ## Clinical Development The vaccine has undergone several clinical trials: - Phase Ia trials in Switzerland with 35 healthy volunteers who received three subcutaneous injections in doses ranging from 10-300 μg on days 0, 30, and 120[3][5] - Phase Ib trials in malaria-endemic regions with both adult and pediatric participants[5] - A proof-of-concept study to assess clinical efficacy when administered subcutaneously to children in Africa[10] In clinical trials, the aluminum hydroxide formulation showed better tolerability and lower reactogenicity compared to Montanide ISA 720 as an adjuvant[3][5][6]. After the third injection in Phase Ia trials, 77% of volunteers developed detectable antibody levels against MSP3-LSP, though these titers decreased significantly by the end of the 12-month follow-up period[3][5]. The vaccine has demonstrated immunogenicity by inducing: - Specific anti-MSP3-LSP antibody responses - Anti-native MSP3 antibody responses - T-cell-specific proliferative responses - Gamma interferon production[6] MSP3-LSP/AlOH represents one of several malaria vaccine candidates currently in clinical development, with researchers hoping it could provide at least 30% protective efficacy against malaria in children[8].

Other names

MSP3-LSP/AlOHMSP3-LSP/Alum