Immunogenic compositions and uses thereof

Abstract

This invention generally relates to immunogenic compositions that comprise an RNA component and a polypeptide component. Immunogenic compositions that deliver antigenic epitopes in two different forms—a first epitope from a pathogen, in RNA-coded form; and a second epitope from the same pathogen, in polypeptide form—are effective in inducing immune response to the pathogen. The invention also relates to a kit comprising an RNA-based priming composition and a polypeptide-based boosting composition. The kit may be used for sequential administration of the priming and the boosting compositions.

What is claimed: 
     
         1 . A method for treating or preventing an infectious disease comprising:
 (i) administering to a subject in need thereof at least once a therapeutically effective amount of a priming composition comprising a self-replicating RNA molecule that encodes a first polypeptide antigen that comprises a first epitope from a pathogen; and   (ii) subsequently administering the subject at least once a therapeutically effective amount of a boosting composition comprising a second polypeptide antigen that comprises a second epitope from said pathogen;   wherein said first epitope and second epitope are the same epitope.   
     
     
         2 . The method of  claim 1 , wherein said first polypeptide antigen and second polypeptide antigen are substantially the same. 
     
     
         3 . The method of  claim 1 , wherein said first polypeptide antigen is a soluble or membrane anchored polypeptide, and said second polypeptide antigen is a soluble polypeptide. 
     
     
         4 . The method of  claim 1 , wherein said first polypeptide antigen is a fusion polypeptide. 
     
     
         5 . The method of  claim 1 , wherein said second polypeptide antigen is a fusion polypeptide. 
     
     
         6 . The method of  claim 1 , wherein the self-replicating RNA is an alphavirus-derived RNA replicon.