Protective antigen of group a streptococci

Abstract

The present invention provides the discovery of a new Streptococcus protective antigen (herein designated Spa) which has been identified and isolated from Streptococci. Spa is a surface antigen distinct from M protein which evokes opsonic antibodies that are protective against multiple serotypes of streptococci. The invention further provides isolated Spa polypeptides, proteins, peptides, and antibodies against the same, as well as nucleic acids encoding Spa polypeptide and peptide antigens. Also provided are methods for identification and isolation of a Spa polypeptide, therapeutic compositions comprised of Spa antigens or antibodies and methods of their use in protecting an animal against a Streptococcus infection.

1 . An isolated peptide that comprises the amino acid sequence set forth in SEQ ID NO:3.  
     
     
         2 . An isolated peptide comprising a  streptococcal  protective antigen (Spa) peptide, wherein the amino acid sequence of the Spa peptide is at least 90% identical to the amino acid sequence set forth in SEQ ID NO:3, and wherein the isolated peptide is capable of eliciting an antibody that opsonizes group A  streptococcus.    
     
     
         3 . The isolated peptide according to  claim 2  wherein the amino acid sequence of the Spa peptide is at least 95% identical to the amino acid sequence set forth in SEQ ID NO:3.  
     
     
         4 . The isolated peptide according to any one of claims  1 - 3  wherein the isolated peptide is capable of eliciting an antibody that opsonizes serotype Type 18 group A  streptococcus.    
     
     
         5 . An isolated polynucleotide comprising a nucleotide sequence that encodes a peptide comprising the amino acid sequence set forth in SEQ ID NO:3.  
     
     
         6 . A vector comprising a promoter operably linked to the polynucleotide according to  claim 5 .  
     
     
         7 . A host cell comprising the vector according to  claim 6 .  
     
     
         8 . A composition comprising the isolated peptide according to any one of claims  1 - 3  and a pharmaceutically acceptable carrier.  
     
     
         9 . The composition according to  claim 8  further comprising an adjuvant.  
     
     
         10 . The composition according to  claim 9  wherein the adjuvant is alum or aluminum hydroxide.  
     
     
         11 . A method for eliciting an antibody that opsonizes group A  streptococcus  in a host, said method comprising administering to the host the composition according to  claim 8 .  
     
     
         12 . The method according to  claim 11  further comprising an adjuvant.  
     
     
         13 . The method according to  claim 12  wherein the adjuvant is alum or aluminum hydroxide.  
     
     
         14 . A method of protecting an animal against a group A  streptococcus  infection, said method comprising administering to the animal the composition according to  claim 8  and a pharmaceutically acceptable carrier.  
     
     
         15 . The method according to  claim 14  wherein the composition further comprises an adjuvant.  
     
     
         16 . The method according to  claim 15  wherein the adjuvant is alum or aluminum hydroxide.  
     
     
         17 . The method according to  claim 14  wherein the animal is human.