Population Genetics of GYPB and Association Study between GYPB*S/s Polymorphism and Susceptibility to P. falciparum Infection in the Brazilian Amazon Eduardo Tarazona-Santos 1. , Lilian Castilho 2. , Daphne R. T. Amaral 2 , Daiane C. Costa 2 , Nata ´lia G. Furlani 3 , Luciana W. Zuccherato 1 , Moara Machado 1 , Marion E. Reid 4 , Mariano G. Zalis 5 , Andre ´a R. Rossit 3¤ , Sidney E. B. Santos 6 , Ricardo L. Machado 3 , Sara Lustigman 7 * 1 Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil, 2 Laborato ´ rio de Pesquisa em Hemoterapia- Hemocentro Campinas, Sa ˜o Paulo, Brazil, 3 Centro de Investigac ¸a ˜o de Microrganismos, Faculdade de Medicina de Sa ˜o Jose ´ do Rio Preto, Sa ˜o Jose ´ do Rio Preto, Brazil, 4 Laboratory of Immunochemistry, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America, 5 Laborato ´ rio de Infectologia e Parasitologia Molecular, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 6 Laborato ´rio de Gene ´tica Humana e Me ´dica, Universidade Federal do Para ´, Belem, Brazil, 7 Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, United States of America Abstract Background: Merozoites of Plasmodium falciparum invade through several pathways using different RBC receptors. Field isolates appear to use a greater variability of these receptors than laboratory isolates. Brazilian field isolates were shown to mostly utilize glycophorin A-independent invasion pathways via glycophorin B (GPB) and/or other receptors. The Brazilian population exhibits extensive polymorphism in blood group antigens, however, no studies have been done to relate the prevalence of the antigens that function as receptors for P. falciparum and the ability of the parasite to invade. Our study aimed to establish whether variation in the GYPB*S/s alleles influences susceptibility to infection with P. falciparum in the admixed population of Brazil. Methods: Two groups of Brazilian Amazonians from Porto Velho were studied: P. falciparum infected individuals (cases); and uninfected individuals who were born and/or have lived in the same endemic region for over ten years, were exposed to infection but have not had malaria over the study period (controls). The GPB Ss phenotype and GYPB*S/s alleles were determined by standard methods. Sixty two Ancestry Informative Markers were genotyped on each individual to estimate admixture and control its potential effect on the association between frequency of GYPB*S and malaria infection. Results: GYPB*S is associated with host susceptibility to infection with P. falciparum; GYPB*S/GYPB*S and GYPB*S/GYPB*s were significantly more prevalent in the in the P. falciparum infected individuals than in the controls (69.87% vs. 49.75%; P,0.02). Moreover, population genetics tests applied on the GYPB exon sequencing data suggest that natural selection shaped the observed pattern of nucleotide diversity. Conclusion: Epidemiological and evolutionary approaches suggest an important role for the GPB receptor in RBC invasion by P. falciparum in Brazilian Amazons. Moreover, an increased susceptibility to infection by this parasite is associated with the GPB S+ variant in this population. Citation: Tarazona-Santos E, Castilho L, Amaral DRT, Costa DC, Furlani NG, et al. (2011) Population Genetics of GYPB and Association Study between GYPB*S/s Polymorphism and Susceptibility to P. falciparum Infection in the Brazilian Amazon. PLoS ONE 6(1): e16123. doi:10.1371/journal.pone.0016123 Editor: Georges Snounou, Universite ´ Pierre et Marie Curie, France Received July 29, 2010; Accepted December 14, 2010; Published January 24, 2011 Copyright: ß 2011 Tarazona-Santos et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This project has been funded in part with federal funds from the National Institute of Allergy and Infectious Diseases, National Institutes of Health number 5R03TW007349-3 and 1R56AI069547-01A2 to SL. This research was also supported in part by the intramural funding of the New York Blood Center to SL and by funding from Brazilian National Research Council (CNPq) to LC, ETS and MM; Sa ˜o Paulo State Research Agency (FAPESP) to LC, DRTA, DCC, NGF, ARBR, RLDM; Minas Gerais State Research Agency (FAPEMIG) to ETS, Brazilian Ministry of Education (CAPES) to LWZ. The Hematology and Hemotherapy Center - Hemocentro UNICAMP, forms part of the National Institute of Science and Technology of Blood, Brazil (INCT do Sangue -CNPq / MCT / FAPESP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: slustigman@nybloodcenter.org . These authors contributed equally to this work ¤ Current address: Departamento de Microbiologia e Parasitologia, Universidade Federal Fluminense, Nitero ´ i, Brazil Introduction Specificity of invasion of Plasmodium falciparum merozoites into human red blood cells (RBCs) was the first indication that malaria parasites possess ligands that recognize and interact exclusively with receptors on the surface of the host RBCs [1]. The specificity of malaria parasites for RBC depends on a number of ligand- receptor interactions that are dynamic in P. falciparum and provide a greater flexibility to the parasite to overcome the variability in host RBCs and to evade immune responses. The P. falciparum PLoS ONE | www.plosone.org 1 January 2011 | Volume 6 | Issue 1 | e16123