Antibodies to a recombinant glutamate-rich Plasmodium falciparum protein: evidence for protection of individuals living in a holoendemic area of Liberia.
A Plasmodium falciparum antigen gene coding for a 220-kD glutamate-rich protein (GLURP) has been cloned, and the 783 C-terminal amino acids of this protein (GLURP489-1271) have been expressed as a beta-galactosidase fusion protein in Escherichia coli. The encoded 783 amino acid residues contain two areas of repeated amino acid sequences. Antibodies against recombinant GLURP489-1271, as well as against a synthetic peptide corresponding to GLURP899-916, and against a synthetic peptide representing the major glutamate rich repeat sequence from the P. falciparum ring erythrocyte surface antigen (Pf155/RESA) (EENV)6 were examined in 423 individuals (age range 30 days-78 years) living in a malaria holoendemic area of Liberia. In the 5-9-year-old age group, subjects with anti-GLURP489-1271 antibody concentrations greater than the mean value of the group had lower parasite densities than those with low antibody concentrations (P = 0.0151). High levels of anti-GLURP899-916 antibodies did not correlate with low parasite densities. However, high levels of anti-(EENV)6 antibodies were associated with significantly lower parasite densities in the 2-4-year-old age group (P = 0.0189). There was no correlation between the anti-GLURP489-1271 and anti-(EENV)6 antibody responses. The data provide indirect evidence for a protective role of antibodies reacting with recombinant GLURP489-1271 as well as with the synthetic peptide (EENV)6 from the Pf155/RESA.
Hogh
B
B
Department of Infection-Immunology, Statens Seruminstitut, Copenhagen, Denmark.
Petersen
E
E
Dziegiel
M
M
David
K
K
Hanson
A
A
Borre
M
M
Holm
A
A
Vuust
J
J
Jepsen
S
S
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007988:Liberia / Q000453:epidemiology; D016778:Malaria, Falciparum / Q000453:epidemiology / Q000517:prevention & control*; D008875:Middle Aged; D008969:Molecular Sequence Data; D015800:Protozoan Proteins / Q000737:chemistry / Q000276:immunology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000276:immunology; D012091:Repetitive Sequences, Nucleic Acid
D000913:Antibodies, Protozoan; D015800:Protozoan Proteins; D011994:Recombinant Proteins; C072492:glutamate-rich protein, Plasmodium