Identification of an erythrocyte binding peptide from the erythrocyte binding antigen, EBA-175, which blocks parasite multiplication and induces peptide-blocking antibodies.
A biotinylated peptide covering a sequence of 21 amino acids (aa) from the erythrocyte binding antigen (EBA-175) of Plasmodium falciparum bound to human glycophorin A, an erythrocyte receptor for merozoites, as demonstrated by enzyme-linked immunosorbent assay (ELISA) and to erythrocytes as demonstrated by flow cytometry analysis. The peptide, EBA(aa1076-96), also bound to desialylated glycophorin A and glycophorin B when tested by ELISA. The peptide blocked parasite multiplication in vitro. The glycophorin A binding sequence was further delineated to a 12-aa sequence, EBA(aa1085-96), by testing the binding of a range of truncated peptides to immobilized glycophorin A. Our data indicate that EBA(aa1085-96) is part of a ligand on the merozoite for binding to erythrocyte receptors. This binding suggests that the EBA(aa1085-96) peptide is involved in a second binding step, independent of sialic acid. Antibody recognition of this peptide sequence may protect against merozoite invasion, but only a small proportion of sera from adults from different areas of malaria transmission showed antibody reactivities to the EBA(aa1076-96) peptide, indicating that this sequence is only weakly immunogenic during P. falciparum infections in humans. However, Tanzanian children with acute clinical malaria showed high immunoglobulin G reactivity to the EBA(aa1076-96) peptide compared to children with asymptomatic P. falciparum infections. The EBA(aa1076-96) peptide sequence from EBA-175 induced antibody formation in mice after conjugation of the peptide with purified protein derivative. These murine sera inhibited EBA(aa1076-96) peptide binding to glycophorin A.
Jakobsen
P H
PH
Centre for Medical Parasitology, Department of Infectious Diseases, State University Hospital (Rigshospitalet), University of Copenhagen,, Copenhagen, Denmark.
Heegaard
P M
PM
Koch
C
C
Wasniowska
K
K
Lemnge
M M
MM
Jensen
J B
JB
Sim
B K
BK
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D002352:Carrier Proteins / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D004912:Erythrocytes / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000097:blood / Q000453:epidemiology / Q000276:immunology* / Q000517:prevention & control; D051379:Mice; D008807:Mice, Inbred BALB C; D008875:Middle Aged; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects / Q000254:growth & development / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D016052:Protozoan Vaccines / Q000276:immunology; D018074:Vaccines, Conjugate / Q000276:immunology
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D002352:Carrier Proteins; D010455:Peptides; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; D018074:Vaccines, Conjugate; C065668:erythrocyte-binding antigen 175, Plasmodium