Vaccine containing a thiol protease

Abstract

The invention relates to the use of thiol proteases having Cathepsin L type activity in the formulation of vaccines for combating helminth parasites. Preferably the protease is derived from a fluke such as Fasciola hepatica.

1 . A vaccine for use in combatting a parasitic infestation of helminths in a mammal comprising antigenic material, wherein said antigenic material comprises a  Fasciola hepatica  protease having Cathepsin L2 activity and being at least 95% pure, or an antigenic fragment or epitope thereof, together with an adjuvant.  
     
     
         2 . The vaccine of  claim 1 , wherein the protease having Cathepsin L2 activity has a molecular weight of 29 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis under reducing conditions.  
     
     
         3 . The vaccine of  claim 2 , wherein the protease having Cathepsin L2 activity has an N-terminal amino acid sequnce of A V P D K I D R R E S G. [SEQ. ID NO: 23] 
     
     
         4 . The vaccine of  claim 1 , which further comprises a carrier.  
     
     
         5 . The vaccine of  claim 1 , which further comprises one or more purified antigenic proteins.  
     
     
         6 . The vaccine of  claim 5 , wherein said purified antigenic proteins are excretory/secretory proteins.  
     
     
         7 . Cathepsin L2 having molecular weight of 29 kDa by sodium dodecyl sulphate polyacrylamide gel electrophoresis under reducing conditions.  
     
     
         8 . A method of combatting a parasitic infestation of helminths in a mammal comprising administering to said mammal a vaccine as claimed in  claim 1  in an amount effective to combat said infestation.  
     
     
         9 . The method of  claim 8 , wherein the protease having Cathepsin L2 activity has an N-terminal amino acid sequence of A V P D K I D R R E S G.  
     
     
         10 . The method of  claim 8 , wherein said effective amount is within the range of 10-500 μg.  
     
     
         11 . A protease having Cathepsin L2 activity or a proenzyme thereof or an antigenic fragment or epitope thereof produced by recombinant DNA techniques.  
     
     
         12 . A DNA molecule encoding a protease, proenzyme, fragment or epitope as claimed in  claim 11.