Epigallocatechin gallate, the main component of tea polyphenol, binds to CD4 and interferes with gp120 binding.
BACKGROUND
Epigallocatechin gallate (EGCG), the major component of tea polyphenol, has been reported to have various physiologic modulatory activities. Several reports also have shown that catechin has a protective effect against HIV infection, part of which is mediated by inhibiting virions to bind to the target cell surface.


OBJECTIVE
We investigated the effect of EGCG on the expression of CD4 molecules and on its ability to bind gp120, an envelope protein of HIV-1.


METHODS
Peripheral blood CD4+ T cells were incubated in the presence of EGCG, and the expression of CD4 was evaluated by means of flow cytometry. The effect of EGCG on the antibody binding to CD4 was investigated by using a sandwich ELISA, and the effect on the gp120 binding to CD4 was analyzed by means of flow cytometry.


RESULTS
EGCG efficiently inhibited binding of anti-CD4 antibody to its corresponding antigen. This effect was mediated by the direct binding of EGCG to the CD4 molecule, with consequent inhibition of antibody binding, as well as gp120 binding.


CONCLUSIONS
The present results suggest a potential preventive effect of EGCG on HIV-1 infection by modulating binding to CD4.
Kawai
Kazushige
K
Department of Surgical Oncology, Faculty of Medicine, the University of Tokyo, Japan.
Tsuno
Nelson H
NH
Kitayama
Joji
J
Okaji
Yurai
Y
Yazawa
Kentaro
K
Asakage
Masahiro
M
Hori
Nobukazu
N
Watanabe
Toshiaki
T
Takahashi
Koki
K
Nagawa
Hirokazu
H
D000911:Antibodies, Monoclonal / Q000187:drug effects / Q000276:immunology; D000998:Antiviral Agents / Q000378:metabolism*; D015704:CD4 Antigens / Q000187:drug effects / Q000276:immunology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000276:immunology* / Q000494:pharmacology*; D002478:Cells, Cultured; D004705:Endocytosis / Q000187:drug effects; D005419:Flavonoids / Q000737:chemistry; D015699:HIV Envelope Protein gp120 / Q000187:drug effects* / Q000378:metabolism*; D006801:Humans; D007938:Leukemia / Q000378:metabolism / Q000473:pathology; D010636:Phenols / Q000737:chemistry; D059808:Polyphenols; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D013662:Tea / Q000737:chemistry
D000911:Antibodies, Monoclonal; D000998:Antiviral Agents; D015704:CD4 Antigens; D005419:Flavonoids; D015699:HIV Envelope Protein gp120; D010636:Phenols; D059808:Polyphenols; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate