title: Comparative population structure of Plasmodium falciparum circumsporozoite protein NANP repeat lengths in Lilongwe, Malawi.
abstract: Humoral immunity to Plasmodium falciparum circumsporozoite protein is partly mediated by a polymorphic NANP tetra-amino acid repeat. Antibody response to these repeats is the best correlate of protective immunity to the RTS,S malaria vaccine, but few descriptions of the natural variation of these repeats exist. Using capillary electrophoresis to determine the distribution of NANP repeat size polymorphisms among 98 isolates from Lilongwe, Malawi, we characterised the diversity of P. falciparum infection by several ecological indices. Infection by multiple distinct variants was common, and 20 distinct repeat sizes were identified. Diversity of P. falciparum appeared greater in children (18 variants) than adults (12 variants). There was evidence of genetic distance between different geographic regions by Nei's Standard Genetic Distance, suggesting parasite populations vary locally. We show that P. falciparum is very diverse with respect to NANP repeat length even on a local level and that diversity appears higher in children.
authors.affiliation: University of North Carolina-Chapel Hill, Department of Medicine, Division of Infectious Diseases, Chapel Hill, NC, USA. nbowman@med.unc.edu
authors.forename: Natalie M
authors.initials: NM
authors.lastname: Bowman
authors.forename: Seth
authors.initials: S
authors.lastname: Congdon
authors.forename: Tisungane
authors.initials: T
authors.lastname: Mvalo
authors.forename: Jaymin C
authors.initials: JC
authors.lastname: Patel
authors.forename: Veronica
authors.initials: V
authors.lastname: Escamilla
authors.forename: Michael
authors.initials: M
authors.lastname: Emch
authors.forename: Francis
authors.initials: F
authors.lastname: Martinson
authors.forename: Irving
authors.initials: I
authors.lastname: Hoffman
authors.forename: Steven R
authors.initials: SR
authors.lastname: Meshnick
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Juliano
mesh_terms: D000328:Adult; D000818:Animals; D002648:Child; D002675:Child, Preschool; D019075:Electrophoresis, Capillary; D005260:Female; D006801:Humans; D008295:Malawi; D008297:Male; D010963:Plasmodium falciparum / Q000378:metabolism*; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan