Genetic polymorphisms in the glutamate-rich protein of
Plasmodium falciparum field isolates from a malaria-endemic
area of Brazil |
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Authors: | Lilian Rose Pratt-Riccio Daiana de Souza Perce-da-Silva Josué da Costa Lima-Junior Michael Theisen Fátima Santos Cláudio Tadeu Daniel-Ribeiro Joseli de Oliveira-Ferreira Dalma Maria Banic |
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Institution: | 1.Laboratório de Pesquisas em Malária;2.Laboratório de Simulídeos e Oncocercose;3.Laboratório de Imunoparasitologia, Instituto Oswaldo Cruz-Fiocruz, Rio de Janeiro, RJ, Brasil;4.Statens Seruminstitut, Copenhagen, Denmark;5.Laboratório de Entomologia, Laboratório Central Porto Velho, Porto Velho, RO, Brasil |
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Abstract: | The genetic diversity displayed by Plasmodium
falciparum, the most deadly Plasmodium species, is
a significant obstacle for effective malaria vaccine development. In this study,
we identified genetic polymorphisms in P. falciparum
glutamate-rich protein (GLURP), which is currently being tested in clinical
trials as a malaria vaccine candidate, from isolates found circulating in the
Brazilian Amazon at variable transmission levels. The study was performed using
samples collected in 1993 and 2008 from rural villages situated near Porto
Velho, in the state of Rondônia. DNA was extracted from 126 P.
falciparum-positive thick blood smears using the phenol-chloroform
method and subjected to a nested polymerase chain reaction protocol with
specific primers against two immunodominant regions of GLURP, R0 and R2. Only
one R0 fragment and four variants of the R2 fragment were detected. No
differences were observed between the two time points with regard to the
frequencies of the fragment variants. Mixed infections were uncommon. Our
results demonstrate conservation of GLURP-R0 and limited polymorphic variation
of GLURP-R2 in P. falciparum isolates from individuals living
in Porto Velho. This is an important finding, as genetic polymorphisms in B and
T-cell epitopes could have implications for the immunological properties of the
antigen. |
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Keywords: | Plasmodium falciparum GLURP polymorphism |
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