Plasmids and methods for peptide display and affinity-selection on virus-like particles of rna bacteriophages

Abstract

The present invention relates to a system and method for controlling peptide display valency on virus-like particles (VLPs), especially including MS2 VLPs. In this method, large amounts of wild-type and low quantities of single-chain dimer coat proteins may be produced from a single RNA. Valency is controlled in immunogen (vaccine) production by providing a system that allows the production of large amounts of wild-type and low quantities of single-chain dimer coating proteins from a single RNA, allowing facile adjustment of display valency levels on VLPs, especially MS2 VLPS over a wide range, from few than one—on average—to as many as ninety per particle. This facilitates the production of immunogens and vaccines, including VLPs exhibiting low valency. Nucleic acid constructs useful in the expression of virus-like particles are disclosed, comprised of a coat polypeptide of MS2 modified by insertion of a heterologous peptide, wherein the heterologous peptide is displayed on the virus-like particle and encapsidates MS2 niRNA. Nucleic acid constructs are also disclosed which are useful in the expression of virus-like particles comprised of a coat polypeptide of PP7 modified by insertion of a heterologous peptide, wherein the heterologous peptide is displayed on the virus-like particle and encapsidates PP7 mRNA.

1 .- 151 . (canceled) 
     
     
         152 . An RNA bacteriophage comprising a single chain coat polypeptide dimer having a HPV L2 peptide insertion, the HPV L2 peptide having an amino acid sequence corresponding to QLYKTCKQAGTCPPD. 
     
     
         153 . The RNA bacteriophage of  claim 152 , wherein the HPV L2 peptide is a HPV16 L2 peptide. 
     
     
         154 . The RNA bacteriophage of  claim 152 , wherein the HPV L2 peptide insertion consists essentially the amino acid sequence of QLYKTCKQAGTCPPD. 
     
     
         155 . The RNA bacteriophage of  claim 152 , wherein the RNA bacteriophage has a valency of 90. 
     
     
         156 . The RNA bacteriophage of  claim 152 , wherein the HPV L2 Peptide is inserted in the AB loop of the downstream coat polypeptide of the single chain coat polypeptide dimer. 
     
     
         157 . The RNA bacteriophage of  claim 152 , wherein the HPV L2 Peptide is inserted in the AB loop of the downstream coat polypeptide of the single chain coat polypeptide dimer. 
     
     
         158 . An immunogenic composition comprising the RNA bacteriophage of  claim 152  and an adjuvant.