A simple screening method for detecting bindings between oligopeptides and HLA-DR molecules on filter papers: possible application for mapping of putative helper T-cell epitopes on MSP1 of Plasmodium falciparum.
Binding capacities of synthetic peptides to HLA-DR molecules were tested on filter papers to identify putative helper T-cell epitopes on a malarial protein. The antigen tested was the merozoite surface glycoprotein 1 (MSP1) of Plasmodium falciparum, a vaccine candidate targeting the asexual erythrocytic stage. Bindings between synthetic oligopeptides and HLA-DR molecules were tested. Such bindings were not non-specific, and a known helper T-cell epitope peptide showed positive binding to the restricting HLA-DR molecule. By using this screening system, we observed the unequal distribution of HLA-DR-binding peptides in 10 out of 17 MSP1 blocks tested. Block #6 of MSP1 seemed to show the highest frequency in the positive binding; on the other hand, blocks #1 and #17, both of which were thought to be vaccine candidate regions, contained fewer HLA-DR binding peptides. This was not inconsistent with the results that block #17 was less stimulatory to peripheral T cells than block #6. The peptides with positive binding to HLA-DR showed actual epitope activities when we tested peptide-driven proliferation of human bulk T-cell lines, and association between the two parameters was statistically significant (P<0.001). For more detailed information for vaccine development, peptides with both IgG- and HLA-DR binding activities were mapped in block #17 of MSP1. Together with these results, we demonstrate that our simple screening system seems to provide essential information for vaccine development through uncovering locations of putative epitopes for human helper T cells.
Fu
J
J
Department of Medical Zoology, Faculty of Medicine, Mie University, Tsu, Japan.
Hato
M
M
Igarashi
K
K
Suzuki
T
T
Matsuoka
H
H
Ishii
A
A
Leafasia
J L
JL
Chinzei
Y
Y
Ohta
N
N
D000595:Amino Acid Sequence; D000818:Animals; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006684:HLA-DR Antigens / Q000378:metabolism*; D006801:Humans; D007158:Immunologic Techniques; D008213:Lymphocyte Activation; D020066:Merozoite Surface Protein 1 / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D010963:Plasmodium falciparum / Q000276:immunology* / Q000378:metabolism; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D018984:Epitopes, T-Lymphocyte; D006684:HLA-DR Antigens; D020066:Merozoite Surface Protein 1; D009842:Oligopeptides