Method of using a facilitator of retroviral entry into cells

Abstract

The present invention demonstrates that a receptor, named DC-SIGN, is specifically expressed on dendritic cells, and facilitates infection of T lymphocytes with HIV. Assays for identifying compounds that modulate the interaction of DC-SIGN and HIV and/or T cells and macrophage are provided. Compounds so identified are also part of the present invention.

What is claimed is:  
     
         1 . An antibody that is specific for an antigenic fragment of gp120; wherein said antigenic fragment is obtained from a portion of gp120 selected from the group consisting of the portion of gp120 that binds to DC-SIGN and a portion of gp120 that is that is exposed upon gp120 binding of DC-SIGN due to the concomitant conformational change; wherein said antibody inhibits the trans-enhancement of HIV entry into a T cell or macrophage facilitated by dendritic cells.  
     
     
         2 . The antibody of  claim 1  that is a monoclonal antibody.  
     
     
         3 . An immortal cell line that produces the monoclonal antibody according to  claim 2 .  
     
     
         4 . An antibody that is specific for the DC-SIGN-gp120 binding complex; wherein said antibody inhibits the ability of dendritic cells to facilitate the trans-enhancement of HIV entry into a T cell or macrophage.  
     
     
         5 . A soluble form of human DC-SIGN.  
     
     
         6 . A pharmaceutical composition comprising the soluble form of human DC-SIGN of  claim 5  with a pharmaceutically acceptable carrier.  
     
     
         7 . An immunogenic composition comprising an adjuvant and an antigenic fragment of gp120; wherein said antigenic fragment is obtained from a portion of gp120 selected from the group consisting of the portion of gp120 that binds to DC-SIGN and a portion of gp120 that is that is exposed upon gp120 binding of DC-SIGN due to the concomitant conformational change.  
     
     
         8 . An immunogenic composition comprising an adjuvant and a DC-SIGN-gp120 binding complex.  
     
     
         9 . A mammalian cell that is transfected with a vector encoding human DC-SIGN; wherein said cell can facilitate the trans-enhancement of HIV entry into a T cell or macrophage.  
     
     
         10 . The mammalian cell of  claim 9  that is not a dendritic cell.  
     
     
         11 . The mammalian cell of  claim 9  wherein said cell is attached to a solid support matrix.  
     
     
         12 . A method of filtering a biological fluid to remove a virus expressing an HIV envelope glycoprotein that binds DC-SIGN comprising passing the biological fluid through the cell of  claim 11 .  
     
     
         13 . The mammalian cell of  claim 9  that is a human cell.  
     
     
         14 . A transgenic non-human mammal comprising DNA constructs encoding human CD4, a human translocation promoting agent, and human DC-SIGN, wherein said transgenic non-human mammal is capable of mucosal uptake of HIV, transport of the HIV to lymphatic organs and infection of a target T cell and/or macrophage by HIV; and wherein said infection is greatly enhanced relative to a transgenic non-human mammal that does not contain a DNA construct encoding DC-SIGN.  
     
     
         15 . The transgenic non-human mammal of  claim 14  further comprising a DNA construct encoding human cyclin T.  
     
     
         16 . The transgenic non-human mammal of  claim 15  wherein the human translocation promoting agent is selected from the group consisting of CCR5, CXCR4, CCR2b, CCR3, Bob and Bonzo.  
     
     
         17 . The transgenic non-human mammal of  claim 14  which is a mouse.  
     
     
         18 . A method of treating or preventing HIV infection by inhibiting the trans-enhancement of HIV entry into a T cell or macrophage facilitated by dendritic cells comprising administering a humanized form of the antibody of  claim 1 .  
     
     
         19 . A method of identifying a compound that interferes with the trans-enhancement of HIV entry into a cell comprising: 
 (a) contacting a first cell with a vector in the presence of a test compound, wherein the vector comprises a viral envelope protein that binds DC-SIGN, wherein the first cell expresses DC-SIGN, and wherein a DC-SIGN-viral envelope protein complex forms between the first cell and the vector in the absence of the test compound;    (b) removing unbound vector and test compound from the first cell;    (c) contacting a second cell with the first cell; wherein the second cell is susceptible to entry of vectors comprising the viral envelope protein; and    (d) determining the amount of vector that has entered the second cell; wherein a test compound is identified as a compound that interferes with the trans-enhancement of HIV entry into a cell when the amount of vector entry is less when the test compound is present in step (b) than when it is absent in step (b).    
     
     
         20 . The method of  claim 19  wherein said removing of step (b) comprises washing the unbound vector and the test compound away from first cell.  
     
     
         21 . The method of  claim 19  wherein the second cell is a T cell or macrophage.  
     
     
         22 . The method of  claim 19  wherein the second cell expresses CD4 and a translocation promoting agent selected from the group consisting of CCR5, CXCR4, CCR2b, CCR3, Bonzo, and BOB.  
     
     
         23 . The method of  claim 22  wherein the translocation promoting agent is CCR5 and the viral envelope protein is JRFL.  
     
     
         24 . The method of  claim 19  wherein the vector contains a marker protein and step (c) is performed by detecting the amount of marker protein expressed in the cell.  
     
     
         25 . The method of  claim 24  wherein the marker protein is selected from the group consisting of luciferase and green fluorescent protein.  
     
     
         26 . A compound identified by the method of  claim 19 .  
     
     
         27 . An assay for identifying an agent for use in the treatment or prevention of HIV infection using the transgenic non-human mammal of  claim 16 , comprising: 
 (a) administering a test compound to the transgenic non-human mammal;    (b) infecting the transgenic non-human mammal with a virus having an HIV envelope glycoprotein; and    (c) measuring the ability of the transgenic non-human mammal to resist said infection; wherein a test compound is identified as an agent for use in the treatment or prevention of HIV infection when the measured ability of the transgenic mammal to resist said infection is statistically greater in the presence of said test compound than in the absence of said test compound.    
     
     
         28 . A compound identified by the method of  claim 27 .  
     
     
         29 . A method of identifying a compound that interferes with the trans-enhancement of HIV entry into a cell comprising: 
 (a) contacting a first cell with a vector and a second cell in the presence of a test compound, wherein the vector comprises a viral envelope protein that binds DC-SIGN, wherein the first cell expresses DC-SIGN, wherein a DC-SIGN-viral envelope protein complex forms between the first cell and the vector in the absence of the test compound; and wherein the second cell is susceptible to entry of vectors comprising the viral envelope protein; and    (b) determining the amount of vector that has entered the second cell; wherein a test compound is identified as a compound that interferes with the trans-enhancement of HIV entry into a cell when the amount of vector entry is less in the presence of the test compound than in its absence.    
     
     
         30 . The method of  claim 29  wherein the second cell is a T cell or macrophage.  
     
     
         31 . The method of  claim 29  wherein the second cell expresses CD4 and a translocation promoting agent selected from the group consisting of CCR5, CXCR4, CCR2b, CCR3, Bonzo, and BOB.  
     
     
         32 . The method of  claim 31  wherein the translocation promoting agent is CCR5 and the viral envelope protein is JRFL.  
     
     
         33 . The method of  claim 29  wherein the vector contains a marker protein and step (b) is performed by detecting the amount of marker protein expressed in the cell.  
     
     
         34 . The method of  claim 33  wherein the marker protein is selected from the group consisting of luciferase and green fluorescent protein.  
     
     
         35 . A compound identified by the method of  claim 29.