Humoral response to Plasmodium falciparum antigenic peptides (MSP1, MSP2, and SR-11.1) in subjects living in endemic areas

Introduction: vaccines are the key tools for controlling and eradicating malaria worldwide. Currently, research and development are focused on three types of vaccine candidates that target different life stages of Plasmodium falciparum in humans and the vector. The purpose of this study is to evaluate the humoral response to Plasmodium falciparum antigenic peptides (MSP1, MSP2 and SR11.1) in subjects living in endemic areas. Methods: we conducted a cross-sectional study of serum samples collected from 182 Vietnamese subjects living in endemic areas over a period of 5 months. Whole blood was centrifuged and the serum was aliquoted into cryovials and preserved at -20 degrees C until IgG testing. ELISA was used for total immunoglobulin G (IgG) antibodies testing after peptide coupling with glutaraldehyde. Results: a total of 182 sera samples from Vietnamese subjects living in endemic areas were included. In the different study age groups, total antigenspecific IgG antibodies against Plasmodium falciparum antigenic peptides (MSP-1; MSP-2 and SR-11.1) showed age-dependent distribution. In subjects aged 3-19 years, the level of total antigenspecific IgG antibodies against Plasmodium falciparum were lower than those of the age groups over 20 years of age (p=0.07). Comparison of specific antigen-specific IgG antibody levels with Plasmodium falciparum antigenic peptides MSP-1, MSP-2, and SR-11.1 in the age groups showed a significantly higher mean in MSP-1 and MSP-2 compared to anti-SR-11.1 (p=0.04). Conclusion: this study highlights that the level of specific antibodies against Plasmodium falciparum antigenic peptides (MSP-1; MSP-2 and SR-11.1) is age dependent. Of the three antigenic peptides, MSP-1 and MSP-2 appear to be more immunogenic than SR.11.1. Therefore, SR.11.1 is a macromolecule to the immune system and, from this point of view, appears to be significantly less immunogenic than other peptides.