Genetic Analysis of Erythrocyte Binding Antigen 175 (EBA-175), Apical Membrane Antigen (AMA-1) and Merozoite Surface Protein 3 (MSP-3) Allelic Types in Plasmodium Falciparum Isolates From Rural Area in Senegal

Background: Several of the intended P. falciparum vaccine candidate antigens are highly polymorphic and could render a vaccine ineffective if their antigenic sites were not represented in the vaccine. This study aimed to characterize genetic diversity of vaccine candidate antigens merozoite surface protein-3 (MSP-3), apical membrane antigen-1 (AMA-1) and erythrocyte binding antigen (EBA-175) in P. falciparum isolates from Senegal. Methods: DNA analysis was completed on 170 isolates of P. falciparum collected from Keur Soce in Senegal between 2006 and 2008. Genetic diversity was determined in the three P. falciparum genes by, PCR followed by restriction fragment length polymorphism (RFLP). Results: From 170 samples collected, successful, PCR products were obtained from 135 (79%), 140 (82%) and 128 (75%) for AMA-1, MSP-3 and EBA-175, respectively. The results showed that the EBA-175 gene presented 4 different alleles [EBA-175F_loop (62.3%), EBA-175C_loop (46.1%), EBA-175~400bp (17.6%), EBA-175~360bp (8.4%)]. Regarding the MSP-3 patterns, the analysis revealed the presence of three alleles MSP-3_K1 (49.2%), MSP-3_3D7 (54.2%) and MSP-3~350bp (15%). For AMA-1, the results showed three different alleles AMA-1_K1 (39%), AMA-1_HB3 (33%), AMA-1_3D7 (32%). Conclusion: Characterization of the genetic diversity in Plasmodium isolates from Keur Soce in Senegal in the three genes investigated showed a high degree of polymorphism. These findings are helpful in the formulation of a vaccine considering restricted repertoire populations.