Hepatitis C virus asialoglycoproteins

Abstract

Two Hepatitis C Virus envelope proteins (E1 and E2) are expressed without sialylation. Recombinant expression of these proteins in lower eukaryotes, or in mammalian cells in which terminal glycosylation is blocked, results in recombinant proteins which are more similar to native HCV glycoproteins. When isolated by GNA lectin affinity, the E1 and E2 proteins aggregate into virus-like particles.

1 . A method of producing an antibody which specifically binds to a hepatitis C virus (HCV) glycoprotein having mannose-terminated glycosylation, wherein less than about 10% of the total N-linked carbohydrate on said HCV glycoprotein is sialic acid, wherein said HCV glycoprotein is selected from the group consisting of a glycoprotein expressed from the E1 region of HCV, a glycoprotein expressed from the E2 region of HCV, and aggregates thereof, said method comprising:
 growing a host cell transformed with a structural gene encoding an HCV glycoprotein expressed from the E1 region of HCV or the E2 region of HCV in a suitable culture medium;   causing expression of said structural gene, under conditions inhibiting sialylation;   isolating said HCV glycoprotein from said cell culture by contacting said HCV glycoprotein with a mannose-binding protein specific for mannose-terminated glycoproteins, and isolating the protein that binds to said mannose-binding protein;   administering said isolated HCV glycoprotein to an animal to induce production of antibodies; and   isolating said antibodies.   
   
   
       2 . The method of  claim 1 , wherein the structural gene is linked to a sequence encoding a secretion leader that directs the glycoprotein to the endoplasmic reticulum and said conditions inhibiting sialylation comprise inhibiting transport of glycoproteins from the endoplasmic reticulum to the golgi. 
   
   
       3 . The method of  claim 1 , wherein said mannose-binding protein is GNA. 
   
   
       4 . The method of  claim 1 , wherein said antibody specifically binds to a glycoprotein expressed from the E1 region of HCV. 
   
   
       5 . The method of  claim 1 , wherein said antibody specifically binds to a glycoprotein expressed from the E2 region of HCV. 
   
   
       6 . The method of  claim 1 , wherein said antibody specifically binds to an aggregate of a glycoprotein expressed from the E1 region of HCV and a glycoprotein expressed from the E2 region of HCV. 
   
   
       7 . The method of  claim 1 , wherein said antibody specifically binds to an aggregate of glycoproteins expressed from the E1 region of HCV. 
   
   
       8 . The method of  claim 1 , wherein said antibody specifically binds to an aggregate of glycoproteins expressed from the E2 region of HCV. 
   
   
       9 . The method of  claim 1 , wherein the antibody is a polyclonal antibody.