immunology of infectious and parasitic diseases - XXXVII Congress ...

NATURAL ISOTYPIC RESPONSE AGAINST POTENTIAL VACCINE
CANDIDATE PLASMODIUM FALCIPARUM GLUTAMATE-RICH PROTEIN
(GLURP) IN INDIVIDUALS LIVING IN BRAZILIAN MALARIA-ENDEMIC
AREA.
LILIAN ROSE PRATT RICCIO 1 ; JOSUÉ DA COSTA LIMA-JUNIOR 2 ;
LEONARDO JOSÉ DE MOURA CARVALHO 1 ; MICHAEL THEISEN 3 ; FÁTIMA
SANTOS 4 ; JOSELI DE OLIVEIRA-FERREIRA 2 ; CLÁUDIO TADEU DANIEL-
RIBEIRO 1 & DALMA MARIA BANIC 5
1 Laboratório de Pesquisas em Malária, Instituto Oswaldo Cruz, Fiocruz;
2 Laboratório de Imunoparasitologia, IOC, FIOCRUZ; 3 Statens Seruminstitut,
Copenhagen, Denmark; 4 Laboratório de Entomologia, LACEN, Porto Velho,
Rondônia; 5 Laboratório de Simulídeos e Oncocercose, IOC, FIOCRUZ.
Introduction: The Plasmodium falciparum Glutamate-Rich Protein (GLURP) is
a malaria vaccine candidate undergoing clinical trials. GLURP is expressed in
all developmental stages of the parasite life cycle in human host. Immunoepidemiological
studies have shown a high prevalence of antibodies to GLURP
in adults as well as a significant association between high levels of these
antibodies and low parasite densities and protection against clinical malaria.
Also, a recent study in controlled experimental P. falciparum infections shows
that antibodies to GLURP are acquired during a single short low density of P.
falciparum infection in non-immune individuals. The aim of this study was to
evaluate the antibody response profile induced by GLURP in naturally exposed
individuals from a Brazilian endemic area. Methods and Results: The study
was carried out in the farming area of Colina (CL) and the riverside fishing
community of Ribeirinha (RB), both near the capital of Porto Velho (RO). The
population of CL primarily consists of migrants from non-endemic areas, and
the population of RB consists of natives from the Amazon Basin. The antibody
response against immunodominant regions of the GLURP (R0 and R2) and
synthetic peptides (R0: P3, P4, P5, P8, P9, P10, P11, S3; R2: S4) was
evaluated by ELISA. The results showed a high prevalence of individuals with
antibodies to R0 and R2 regions in both CL and RB groups. Different data have
been reported in an African area of low endemicity, where antibody responses
to R2 were observed in only 16 % of donors. Surprisingly, similar results were
reported in an African area of high endemicity. The R0-induced antibodies were