Protein-energetic malnutrition hinders malaria vaccine-derived cellular and class-switched antibody responses against the Plasmodium vivax circumsporozoite protein in mice.

Malaria continues to afflict hundreds of millions of lives annually, causing substantial fatalities despite available vaccines endorsed by the World Health Organization (WHO). However, these vaccines lack efficacy against Plasmodium vivax (Pv). Concomitantly, a considerable part of residents from several Pv-endemic areas face malnutrition, compromising their immunity to diseases, including malaria. Since our group developed an immunogenic yeast-expressing recombinant Pv circumsporozoite protein (yPvCSP-All_CT epitopes) capable of protecting mice against lethal transgenic parasites, we investigated the influence of malnutrition on vaccine-derived responses in C57Bl/6 mice. Animals subjected to a protein-restricted diet presented protein-energetic malnutrition, diminished vaccine-specific IgG-secreting cells in the bone marrow, and reduced IgG and IgG1 serum titers compared to mice under a control diet. IgM titers remained consistent across groups, suggesting that the nutrition status may influence the antibody affinity maturation. These findings emphasize the pivotal role of proper nutrition in enhancing vaccination immunity against Pv malaria.