Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Infection and Immunity 1189-1196 2009 PAR00003353 ENG Infection and Immunity 0019-9567 ISI:000263416700030 3 10.1128/iai.00780-07 https://www.documentation.ird.fr/hor/PAR00003353 https://www.documentation.ird.fr/intranet/publi/2023-02/010087124.pdf 77 Horizon (IRD) Liver-stage antigen 3 (LSA-3) is a new vaccine candidate that can induce protection against Plasmodium falciparum sporozoite challenge. Using a series of long synthetic peptides (LSP) encompassing most of the 210-kDa LSA-3 protein, a study of the antigenicity of this protein was carried out in 203 inhabitants from the villages of Dielmo (n=143) and Ndiop (n=60) in Senegal (the level of malaria transmission differs in these two villages). Lymphocyte responses to each individual LSA-3 peptide were recorded, some at high prevalences (up to 43%). Antibodies were also detected to each of the 20 peptides, many at high prevalence (up to 84% of responders), and were directed to both nonrepeat and repeat regions. Immune responses to LSA-3 were detectable even in individuals of less than 5 years of age and increased with age and hence exposure to malaria, although they were not directly related to the level of malaria transmission. Thus, several valuable T- and B-cell epitopes were characterized all along the LSA-3 protein, supporting the antigenicity of this P. falciparum vaccine candidate. Finally, antibodies specific for peptide LSP10 located in a nonrepeat region of LSA-3 were found significantly associated with a lower risk of malaria attack over 1 year of daily clinical follow-up in children between the ages of 7 and 15 years, but not in older individuals. 052 UR198 Sénégal