Immunoglobulin response to the low polymorphic Pf113 antigen in children from Lastoursville, South-East of Gabon
Authors: Jean-Bernard Lekana-Douki
Roméo Karl Imboumy-Limoukou
Sidney Maghendi-Nzondo
Carole Eboumbou
Charlene Lady Kouna
Lotfi Bounaadja
Jean Claude Biteghe
Franck Prugnolle
Isabelle Florent
Sophie Mbang
Journal: Acta Tropica (2016)
Discipline: CLINICAL MEDICINE
Keywords: Immunogenicity; Immunoglobulin; P. falciparum; Pf113; Polymorphism.
Affiliations: Centre International de Recherches Médicales de Franceville (CIRMF), Unité de Parasitologie Médicale (UPARAM), BP 769 Franceville, Gabon; Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Sorbonne Universités, Muséum National d'Histoire Naturelle, CNRS, CP52, 57 Rue Cuvier, 75005 Paris, France; Ecole Doctorale Régionale en Infectiologie Tropicale d'Afrique Centrale (ECODRAC), BP 876 Franceville, Gabon. Electronic address: ., Centre International de Recherches Médicales de Franceville (CIRMF), Unité de Parasitologie Médicale (UPARAM), BP 769 Franceville, Gabon., Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245), Sorbonne Universités, Muséum National d'Histoire Naturelle, CNRS, CP52, 57 Rue Cuvier, 75005 Paris, France., Faculty of Medicine and Pharmaceutical Sciences, University of Douala Biological Sciences Unit, BP 2701 Douala, Cameroon., Centre International de Recherches Médicales de Franceville (CIRMF), Unité de Parasitologie Médicale (UPARAM), BP 769 Franceville, Gabon; Ecole Doctorale Régionale en Infectiologie Tropicale d'Afrique Centrale (ECODRAC), BP 876 Franceville, Gabon., Centre International de Recherches Médicales de Franceville (CIRMF), Unité de Parasitologie Médicale (UPARAM), BP 769 Franceville, Gabon; UMR 5290 MIVEGEC (CNRS/IRD/UM), BP, 911 Avenue Agropolis BP 64501, 34394 Montpellier cedex 5, France., Centre International de Recherches Médicales de Franceville (CIRMF), Unité de Parasitologie Médicale (UPARAM), BP 769 Franceville, Gabon; Département de Parasitologie-Mycologie Médecine Tropicale, Faculté de Médecine, Université des Sciences de la Santé, BP 4009 Libreville, Gabon. Electronic address: .

Abstract:  Pf113 is a P. falciparum putatively GPI-anchored protein that has been so far localized at the surface of merozoites, suggesting it could interact with RBC surface during merozoite invasion. Previous studies conducted in Papua New Guinea and in Kenya have revealed that this protein is recognized by natural antibodies in individuals living in malaria-endemic areas and is associated with protective immunity in malaria, further supporting the potential of Pf113 for the development of anti-malaria vaccines. However, in Central Africa, no study on the immunogenicity of this protein has been conducted. Here, we report the characterization of the Pf113 immune response in 103 children by Enzyme-Linked Immunoabsorbent Assay (ELISA), using a recombinant form of Pf113 expressed in Escherichia coli, together with the study of the Pf113 polymorphism, after amplification and sequencing of 40 field isolates. Data showed that almost 51% of the studied individuals had positive antibody responses to the recombinant Pf113 protein, and that IgG subclass response was dominated by IgG3 (84%) followed by IgG1 (50%). Surprisingly the prevalence of IgG4 was 92%. In addition, gene analysis in field isolates from this region indicated that Pf113 was not highly polymorphic, in particular regarding high-activity binding peptides (HABPs). Our data reinforce the idea that Pf113 may be considered for inclusion in multicomponent blood-stage vaccines. 

Retracted: No

PubPeer comments:
 This paper mentions a recruitment between July 2012 and May 2013. The authors also mention that: * This study was authorized by the Ministry of Health and has received the agreement of the National Ethics Committee on Research (authorization number: PROT Nu00b00023 2013 SG CNE) * In accordance with the authorization number, it can be guess with a good confidence that the protocol has been approved in 2013, after the beginning of the recruitment. Can the author explain why the protocol started before to get the ethics approval ? ,