Basic and clinical immunologyEpigallocatechin gallate, the main component of tea polyphenol, binds to CD4 and interferes with gp120 binding
Section snippets
Reagents and antibodies
ECG, EGCG, phorbol 12-myristate 13-acetate (PMA), and anti-β actin mAbs were purchased from Sigma (Saint Louis, Mo). FITC-conjugated or nonconjugated anti-CD11a, anti-CD3, anti-CD54, and anti-CD4 mAbs (clone sk-3) were obtained from BD Pharmingen (San Diego, Calif). The goat polyclonal antibody to CD4 cytoplasmic tail (c-18) was obtained from Santa Cruz Biotechnology (Santa Cruz, Calif), and mouse anti-CD4 mAb (clone no. 34930.111) used for Western blotting and horseradish peroxidase—conjugated
EGCG treatment attenuates the CD4 expression of T cells and leukemia cell lines
As shown in Fig 1, EGCG caused a significant decrease in the expression of CD4 in a dose-dependent manner. The effect was evident with EGCG at 25 μmol/L but more prominent at 50 μmol/L (P < .05 for both doses). Thus the dose of 50 μmol/L EGCG was chosen for the subsequent experiments. The expressions of CD3, CD54, and CD11a, however, were not significantly affected by EGCG. CD54 and CD11a were chosen here because they are important costimulatory molecules in the T-cell activation by
Discussion
Previous reports have demonstrated that EGCG inhibits HIV-1 infection of lymphocytes in multiple manners, and obstruction of viral attachment to the target cells is one of the suggested mechanisms of the anti-HIV-1 effect of EGCG.13, 14 Because the CD4 molecule is the receptor for HIV-1 and the regulation of CD4 expression has an important role in the viral life cycle, in the present study we investigated the mutual interaction between CD4 and EGCG.
Initially, we demonstrated that incubation of
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