Study of the mechanism of caffeoyl glucopyranoses in inhibiting HIV-1 entry using pseudotyped virus system / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the inhibitory activities of caffeoyl glucopyranoses purified from Balanophora japonica Makino on HIV entry and their mechanism.</p><p><b>METHODS</b>HIV-1 Env pseudovirus was used to evaluate the anti-HIV-1 activity of those compounds. ELISA and molecular docking were used to study the mechanism of the actions of the active compounds.</p><p><b>RESULTS</b>We used the HIV-1 Env pseudovirus to test the anti-HIV-1 activity of the six phenolic compounds (final concentration 25 microg/ml), and found that only 1,2,6-Tri-O-caffeoyl-beta-D-glucopyranose (TCGP) and 1,3-Di-O-caffeoyl-4-O-galloyl-beta-D- glucopyranose (DCGGP) could effectively inhibit the entry of HIV-1 Env pseudovirus into the target cells in a dose-dependent manner, with IC(50) values of 5.5-/+0.2 and 5.3-/+0.1 microg/ml, respectively. These two compounds could also blocked the gp41 six-helix bundle formation. Molecular docking analysis suggested that they might bind to the hydrophobic cavity of the gp41 N-trimeric coiled-coil.</p><p><b>CONCLUSION</b>TCGP and DCGGP are potent HIV-1 entry inhibitors targeting gp41 and can serve as lead compounds for developing novel anti-HIV-1 microbicides for prevention of sexual HIV-1 transmission.</p>

VIR576 inhibits antigen-specific T cell activation by binding to the transmembrane domain of T cell receptor / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the mechanism underlying the inhibitory effect of the anti-HIV peptide VIR576 on antigen-specific T cell activation.</p><p><b>METHODS</b>CCK-8 assay was used to investigate the effect of VIR576 on the proliferation of splenocytes of OVA-specific DO11.10 Tg mice in response to chicken OVA. Hemolysis test, hemolysis inhibition assay and fluorescence binding assay were used to investigate the interaction of VIR576 with the transmembrane domain (TMD) of the T cell receptor (TCR).</p><p><b>RESULTS</b>VIR576 inhibited HIV glycoprotein gp41 fusion peptide-mediated antigen specific T cell activation, and VIR576 itself also inhibited splenocyte proliferation in responses to OVA (P<0.05). Hemolysis test, hemolysis inhibition assay and fluorescence binding assay demonstrated that VIR576 suppressed TCR-TMD-mediated hemolysis and competitively inhibited Rho-VIR576 binding to TCR-TMD peptide.</p><p><b>CONCLUSION</b>VIR576 is effective in suppressing the antigen-specific T cell activation via TCR and can interact with TCR-TMD. VIR576 may serve as a potent microbicide candidate to block sexual transmission of HIV due to of its inhibitory effect on both HIV entry and antigen-specific T cell activation.</p>