These same data have also been demonstrated in Senegal, Uganda and Indonesia, where a variation of antibody levels of the vaccine candidates such as AMA1, MSP1 and circumsporozoite protein (CSP) was observed between rural, peri\urban and urban areas 52, 57, 58

These same data have also been demonstrated in Senegal, Uganda and Indonesia, where a variation of antibody levels of the vaccine candidates such as AMA1, MSP1 and circumsporozoite protein (CSP) was observed between rural, peri\urban and urban areas 52, 57, 58. In both study sites, data showed that the level of anti\PfA\M1 antibodies was higher in infected than uninfected children. higher anti\PfA\M1 antibody titers (014??002?AU) than those living in urban areas (008??002 AU, in Gabonese children. Further studies on the role of PfA\M1 during anemia are needed. Keywords: antibody, Gabon, humoral immunity, malaria contamination, aminopeptidase 1 (PfA\M1) Aminopeptidase 1 (PfA\M1) considered as a encouraging drug target candidate, appears also as a possible diagnostic biomarker for malaria transmission intensity in Gabonese children. Indeed, during malaria contamination, antibody Zfp622 response against PfA\M1 increase with contamination, area of residence, and age. So, age\dependent acquired immune response to PfA\M1 suggest that malaria\specific PfA\M1 antibodies may play an important role in the immune response of the host against P. falciparum in this populace. Introduction Despite recent improvements in reducing the burden of malaria in some endemic areas of seasonal or sporadic transmission 1, malaria is still a major public health problem and remains one of the most important causes KPT-6566 of morbidity and mortality in many sub\Saharan African countries. According to the World Health Organization, approximately 216 million people were infected and 445 000 deaths due to malaria occurred worldwide KPT-6566 in 2016 2. In addition, more than 90% of the deaths due to malaria in sub\Saharan Africa occur in children aged under 5?years, with being the most virulent species. Indeed, 285?000 deaths due to malaria were recorded in this populace in 2016 2. Intensified malaria control strategies have resulted in a decline in deaths by malaria in recent years; therefore, many countries are turning to malaria eradication programs 3, 4. In order to lead an effective eradication of malaria transmission a combination of control strategies is necessary, which includes the use of quick diagnostic tests for all those suspected cases of malaria, artemisinin\based combination therapy, insecticide\treated nets, interior residual sprays, intermittent preventive treatment for pregnant women 4, 5, 6 and the development of an effective malaria vaccine. The use of passive transfer of immunoglobulin from immune African adults to treat children infected with and with severe malaria provides evidence that antibodies are important mediators in the protective response to malaria 7. The induction of this protective humoral immune response is an essential element which supports the efforts of the malaria research community towards development of an effective vaccine against malaria. Thus, several parasite antigens were identified as targets of natural immunity, among which a vast majority are expressed during the blood stage. Indeed, vaccines targeting antigens expressed during the blood stage have been evaluated for their ability to prevent the disease 8, 9, 10, 11. Many studies suggest that protection against malaria depends on high concentrations of antibodies 12, 13, 14, 15, 16. Previous studies have shown that high levels of antibodies to apical membrane antigen 1 (AMA\1), merozoite surface protein 1 (MSP1C19) and MSP2 are significantly associated with protection against clinical malaria in older children 13. The anti\erythrocyte\binding antigen 140 (EBA140), EBA175 and EBA181 responses were associated most particularly with protection against clinical malaria in older children 14, but were also associated with a higher risk of clinical malaria in young children. In young children who acquire immunity, higher levels of antibodies to merozoite antigens are not protective but rather predictive of an increased risk of malaria development. Also, the anti\MSP2, AMA\1, EBA175, EBA140 and EBA181 responses were significantly associated with an increased risk of malaria in young children. Interestingly, the responses to MSP1\19 were not significantly associated with this risk 17. Similarly, anti\glutamate\rich protein region KPT-6566 KPT-6566 2 (GLURP\R2) antibodies were associated with reduced risk of symptomatic malaria contamination in African children 18. However, although antibodies to merozoite antigens are considered important targets of protective antibodies, epidemiological evidence of the protective effect of naturally acquired anti\merozoite responses is not specific, and studies in different cohorts or areas of transmission sometimes provide conflicting results 19. There could be many reasons for these inconsistencies. In malaria\endemic areas the rate at which natural immunity develops is dependent on age, intensity, stability of exposure, endemicity of malaria and clinical incidence 19. Other considerations in immuno\epidemiological studies, such as acknowledgement of multiple antigens in combination rather than just a single antigen, are probably required for protection 20, 21. Also, although merozoite antigens have been of particular desire for the search for vaccine candidates, it would be useful.