TY - JOUR
T1 - Thrombin activates envelope glycoproteins of HIV type 1 and enhances fusion
AU - Ling, Hong
AU - Xiao, Peng
AU - Usami, Osamu
AU - Hattori, Toshio
N1 - Funding Information:
This work was supported by Grant-in-Aid for Scientific Research B from JSPS and the Scientific Research Expenses for Health and Welfare Program from the Ministry of Health and Welfare, Japan. The authors are grateful to Dr. S. Zolla-Pazner for MAbs against V2, V3 and gp41, to Dr. R.C. Gallo for H9/IIIB. The authors are also indebted to Dr. J.A. Hoxie for MAb 12G5, to Dr. M.R. Posner for MAb F105, to Dr. J. Robinson for MAb 17b, to Dr. B. Chesebro for MAb 902, to Dr. Michael Emerman for MAGI cell line through AIDS Research and Reference Reagent Program, National Institutes of Health. The authors thank Dr. J.P. Laman for MAb IIIB-V3-21, to Dr. T. Muster for MAb 2F5 through the EU Programme EVA/MRC Centralised Facility for AIDS Reagents, NIBSC, UK (Grant No. QLK2-CT-1999-00609 and GP828102).
PY - 2004/4
Y1 - 2004/4
N2 - To elucidate the roles of serine proteases, including thrombin, in HIV infection, we treated H9 cells infected with HIV-1 LAI virus (H9/IIIB) with four different proteases (thrombin, cathepsin G, trypsin and chymotrypsin) and observed their effects on functional epitopes on both gp120 and gp41 by using flow cytometry. Monoclonal antibodies (MAbs) against the V3 loop, V2 loop, CD4 binding site, coreceptor binding site and gp41 were used. It was found that trypsin decreased the binding of all MAbs except for one MAb against the V3 loop (IIIB-V3-21). Chymotrypsin and cathepsin G did not show any remarkable effect on the antigen expression. On the other hand, thrombin decreased the reactivities of two out of four anti-V3 MAbs and increased the exposure of functional gp120 epitopes including the coreceptor binding site and CD4 binding site. Thrombin also increased the expression of 2F5 antigen (a neutralizing epitope of gp41) but had no effect on other gp41 epitopes. The effect of trypsin or thrombin on HIV-induced cell fusion was examined through co-culturing H9/IIIB and MAGI cells. Trypsin slightly inhibited fusion. Fusion was significantly enhanced in a dose-dependent manner by thrombin, and a 280% increase at 5 U/ml (P < 0.001) was observed. In conclusion, thrombin, one of the major inflammatory molecules in blood, facilitates HIV-induced cell fusion, probably by activating gp120.
AB - To elucidate the roles of serine proteases, including thrombin, in HIV infection, we treated H9 cells infected with HIV-1 LAI virus (H9/IIIB) with four different proteases (thrombin, cathepsin G, trypsin and chymotrypsin) and observed their effects on functional epitopes on both gp120 and gp41 by using flow cytometry. Monoclonal antibodies (MAbs) against the V3 loop, V2 loop, CD4 binding site, coreceptor binding site and gp41 were used. It was found that trypsin decreased the binding of all MAbs except for one MAb against the V3 loop (IIIB-V3-21). Chymotrypsin and cathepsin G did not show any remarkable effect on the antigen expression. On the other hand, thrombin decreased the reactivities of two out of four anti-V3 MAbs and increased the exposure of functional gp120 epitopes including the coreceptor binding site and CD4 binding site. Thrombin also increased the expression of 2F5 antigen (a neutralizing epitope of gp41) but had no effect on other gp41 epitopes. The effect of trypsin or thrombin on HIV-induced cell fusion was examined through co-culturing H9/IIIB and MAGI cells. Trypsin slightly inhibited fusion. Fusion was significantly enhanced in a dose-dependent manner by thrombin, and a 280% increase at 5 U/ml (P < 0.001) was observed. In conclusion, thrombin, one of the major inflammatory molecules in blood, facilitates HIV-induced cell fusion, probably by activating gp120.
KW - BS
KW - Binding site
KW - Envelope
KW - Fusion
KW - HIV
KW - HIV-1
KW - Human immunodeficiency virus
KW - MFI
KW - Mean fluorescence intensity
KW - PBS
KW - Phosphate-buffered saline
KW - Thrombin
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U2 - 10.1016/j.micinf.2004.01.010
DO - 10.1016/j.micinf.2004.01.010
M3 - Article
C2 - 15109955
AN - SCOPUS:1942517392
VL - 6
SP - 414
EP - 420
JO - Microbes and Infection
JF - Microbes and Infection
SN - 1286-4579
IS - 5
ER -