Immunoconjugates comprising cd4 and immunoglobin molecules for the treatment of hiv infection

Abstract

Nucleic acids encoding recombinant CD4-fusion proteins are disclosed herein that include a CD4 polypeptide ligated at its C-terminus with a portion of an immunoglobulin comprising a hinge region and a constant domain of a mammalian immunoglobulin heavy chain. The portion of the IgG is fused at its C-terminus with a polypeptide comprising a tailpiece from the C terminus of the heavy chain of an IgA antibody or a tailpiece from a C terminus of the heavy chain of an IgM antibody. Also disclosed herein are methods for using these CD4-fusion proteins.

1 . An isolated nucleic acid encoding a recombinant polypeptide comprising a CD4 polypeptide ligated at its C-terminus with an immunoglobulin polypeptide, wherein the immunoglobulin polypeptide comprises a hinge region and a constant domain of a mammalian immunoglobulin heavy chain, and wherein the immunoglobulin polypeptide is fused at its C-terminus with a tailpiece polypeptide from the C terminus of the heavy chain of an IgA antibody or a tailpiece from a C terminus of the heavy chain of an IgM antibody. 
     
     
         2 . The isolated nucleic acid of  claim 1 , operably linked to a promoter. 
     
     
         3 . A vector comprising the nucleic acid of  claim 2 . 
     
     
         4 . The vector of  claim 3 , further comprising a selectable marker. 
     
     
         5 . A host cell comprising the nucleic acid of  claim 2 . 
     
     
         6 . The host cell of  claim 5 , wherein the host cell is a mammalian host cell. 
     
     
         7 . The host cell of  claim 6 , wherein the host cell is a human host cell. 
     
     
         8 . A method of inhibiting entry of an immunodeficiency virus into a T cell, comprising
 contacting the virus with a recombinant polypeptide comprising a CD4 polypeptide ligated at its C-terminus with an immunoglobulin polypeptide, wherein the immunoglobulin polypeptide comprises a hinge region and a constant domain of a mammalian immunoglobulin heavy chain, and wherein the immunoglobulin polypeptide is fused at its C-terminus with a tailpiece polypeptide from the C terminus of the heavy chain of an IgA antibody or a tailpiece from a C terminus of the heavy chain of an IgM antibody, thereby inhibiting the entry of the virus into the cell.   
     
     
         9 . The method of  claim 8 , wherein the virus is human immunodeficiency virus type 1 (HIV-1). 
     
     
         10 . The method of  claim 8 , wherein the T cell is a CD4+ T cell. 
     
     
         11 . The method of  claim 8 , wherein the inhibition of entry of the virus in the T cell results in decreased replication of the virus. 
     
     
         12 . A method for inhibiting the interaction of a gp120 polypeptide with a cellular receptor on a T cell, comprising
 contacting the gp120 with the polypeptide comprising a CD4 polypeptide ligated at its C-terminus with an immunoglobulin polypeptide, wherein the immunoglobulin polypeptide comprises a hinge region and a constant domain of a mammalian immunoglobulin heavy chain, and wherein the immunoglobulin polypeptide is fused at its C-terminus with a tailpiece polypeptide from the C terminus of the heavy chain of an IgA antibody or a tailpiece from a C terminus of the heavy chain of an IgM antibody, thereby inhibiting the interaction of the gp120 with the cellular receptor.   
     
     
         13 . The method of  claim 12 , wherein the cellular receptor is CD4, CCR5, or CXCR4. 
     
     
         14 . The method of  claim 12 , wherein the gp120 is on a human immunodeficiency type 1 (HIV-1). 
     
     
         15 . The method of  claim 12 , wherein the T cell is in vitro. 
     
     
         16 . The method of  claim 12 , wherein the T cell is in vivo. 
     
     
         17 . A method of inducing natural killer cell mediated antibody dependent cell-mediated cytotoxicity against a cell infected with an immunodeficiency virus, comprising:
 contacting the cell infected with the immunodeficiency virus with an effective amount a CD4 polypeptide ligated at its C-terminus with an immunoglobulin polypeptide, wherein the immunoglobulin polypeptide comprises a hinge region and a constant domain of a mammalian immunoglobulin heavy chain, and wherein the immunoglobulin polypeptide is fused at its C-terminus with a tailpiece polypeptide from the C terminus of the heavy chain of an IgA antibody or a tailpiece from a C terminus of the heavy chain of an IgM antibody in the presence of the antigen presenting cell or the natural killer cell, thereby inducing antibody dependent cell mediated cytotoxicity of the cell infected with the immunodeficiency virus.   
     
     
         18 . The method of  claim 17 , wherein the antigen presenting cell is a macrophage, a dendritic cell, a B-lymphocyte, or a neutrophil. 
     
     
         19 . The method of  claim 17 , wherein the cell is in vivo. 
     
     
         20 . The method of  claim 17 , wherein the cell is ex vivo. 
     
     
         21 . The method of  claim 17 , wherein the immunodeficiency virus is human immunodeficiency virus type 1 (HIV-1). 
     
     
         22 . A method for stimulating a natural killer cell or an antigen presenting cell, comprising,
 contacting the natural killer cell or the antigen presenting cells with a CD4 polypeptide ligated at its C-terminus with an immunoglobulin polypeptide, wherein the immunoglobulin polypeptide comprises a hinge region and a constant domain of a mammalian immunoglobulin heavy chain, and wherein the immunoglobulin polypeptide is fused at its C-terminus with a tailpiece polypeptide from the C terminus of the heavy chain of an IgA antibody or a tailpiece from a C terminus of the heavy chain of an IgM antibody, thereby stimulating the natural killer cell or antigen presenting cell.   
     
     
         23 . The method of  claim 22 , wherein the natural killer cell is in vitro. 
     
     
         24 . The method of  claim 22 , wherein the natural killer cell is in vivo.