Virus strains

Abstract

The present invention relates to clinical herpes simplex virus (HSV) isolates with improved oncolytic capabilities as compared to reference laboratory HSV strains. The present invention also relates to methods of producing HSV strains of the invention and to pharmaceutical compositions comprising a HSV strain of the invention.

1 - 61 . (canceled) 
   
   
       62 . A modified, oncolytic herpes simplex virus (HSV) strain comprising: a modified, oncolytic herpes simplex virus (HSV) strain wherein said HSV strain is a clinical isolate from a recurrent cold sore and has a greater ability than a reference laboratory HSV strain modified in the same manner as the clinical isolate to replicate in or kill tumor cells, and wherein said reference laboratory HSV strain is selected from the group consisting of HSV1 strain 17+, HSV1 strain F and HSV1 strain KOS. 
   
   
       63 . An HSV strain according to  claim 62 , which is modified such that it lacks one or more genes selected from the group consisting of a functional ICP34.5-encoding gene, a functional ICP6-encoding gene, a functional glycoprotein H-encoding gene and a functional thymidine kinase-encoding gene. 
   
   
       64 . An HSV strain according to  claim 63 , which lacks a functional ICP34.5-encoding gene. 
   
   
       65 . An HSV strain according to  claim 64 , which further lacks a functional ICP47 gene. 
   
   
       66 . An HSV strain according to  claim 62 , which comprises a heterologous gene. 
   
   
       67 . An HSV strain according to  claim 66 , wherein said heterologous gene is a gene capable of modifying immune responses. 
   
   
       68 . An HSV strain according to  claim 67 , wherein said gene capable of modifying immune responses is selected from the group consisting of a gene that encodes an immune stimulatory polypeptide, a gene product capable of modifying immune responses, a prodrug activator, a tumor suppressor or a pro-apoptotic gene product. 
   
   
       69 . An HSV strain according to  claim 68 , wherein the immune stimulatory polypeptide is selected from the group consisting of granulocyte macrophage colony-stimulating factor (GMCSF), a cytokine, a chemokine, RANTES, B7.1, B7.2 or IL12; wherein the prodrug activator is nitroreductase or cytochrome p45; or wherein the tumor suppressor is p53. 
   
   
       70 . An HSV1 strain according to  claim 62 , which is modified such that it lacks a functional ICP34.5 gene, and optionally a functional ICP47 gene; and optionally further comprises a heterologous gene encoding GMCSF. 
   
   
       71 . A pharmaceutical composition comprising a HSV strain according to  claim 62  and a pharmaceutically acceptable carrier or diluent. 
   
   
       72 . A method of determining whether a gene enhances the anti-tumor effects of a herpes simplex virus (HSV) strain comprising:
 (i) providing an HSV according to  claim 62 ;   (ii) inserting a gene to be evaluated into said HSV strain to create a modified, oncolytic HSV strain; and   (iii) assessing the ability of said modified, oncolytic HSV strain to replicate in or kill tumor cells compared to the ability of the precursor strain provided in step (i).   
   
   
       73 . A method of determining the suitability of a herpes simplex virus (HSV) strain for use in the production of a modified, oncolytic HSV strain, wherein said HSV strain is a clinical isolate, said method comprising:
 (i) providing an HSV virus strain to be evaluated;   (ii) assessing the ability of said HSV to replicate in or kill tumor cells; and,   
     selecting for modification HSV strains which have a greater ability than one or more reference strains selected from the group consisting of HSV1 strain 17+, HSV1 strain F and HSV1 strain KOS, to replicate in or kill tumor cells. 
   
   
       74 . A method of producing a modified oncolytic herpes simplex virus (HSV) strain, wherein said HSV strain is a clinical isolate, said method comprising:
 (i) providing an HSV strain selected by a method according to  claim 73 ;   (ii) modifying said strain by rendering non-functional one or more genes selected from the genes encoding ICP34.5, ICP6 and thymidine kinase to create a modified, oncolytic non-laboratory strain; and   (iii) assessing the ability of said modified, oncolytic non-laboratory strain to kill tumor cells.   
   
   
       75 . A method according to  claim 74  wherein the tumor cell-killing capacity of said modified, oncolytic HSV strain is measured by comparison to the tumor cell-killing capacity of a reference laboratory strain with the same gene or genes rendered non-functional, which reference laboratory strain is selected from HSV1 strain 17+, HSV1 strain F and HSV1 strain KOS. 
   
   
       76 . A method according to  claim 73 , wherein said HSV strain is isolated from a host. 
   
   
       77 . A method according to  claim 73 , wherein said HSV strain is a clinical isolate from a recurrent cold sore.