Antibodies and methods for generating genetically altered antibodies with enhanced effector function

Abstract

Dominant negative alleles of human mismatch repair genes can be used to generate hypermutable cells and organisms. By introducing these genes into cells and transgenic animals, new cell lines and animal varieties with novel and useful properties can be prepared more efficiently than by relying on the natural rate of mutation. These methods are useful for generating genetic diversity within immunoglobulin genes directed against an antigen of interest to produce altered antibodies with enhanced biochemical activity. Moreover, these methods are useful for generating antibody-producing cells with increased level of antibody production. The invention also provides methods for increasing the effector function of monoclonal antibodies and monoclonal antibodies with increased effector function.

1 . A method of producing an antibody with enhanced effector function comprising introducing into an antibody-producing cell a dominant negative allele of a mismatch repair gene, whereby said antibody-producing cell becomes hypermutable; screening said hypermutable cells for cells that produce antibodies with increased effector function, thereby producing an antibody with enhanced effector function.  
     
     
         2 . The method of  claim 1  wherein said dominant negative allele is a PMS2 allele.  
     
     
         3 . The method of  claim 2  wherein said PMS2 allele comprises a truncation mutation at codon 134.  
     
     
         4 . The method of  claim 3  wherein said truncation mutation is a thymidine at nucleotide 424 of wild-type PMS2.  
     
     
         5 . The method of  claim 3  wherein said PMS2 allele encodes the first 133 amino acids of wild-type PMS2.  
     
     
         6 . The method of  claim 2  wherein the PMS2 allele is human PMS2.  
     
     
         7 . The method of  claim 1  wherein said effector function is antibody-dependent cytotoxicity (ADCC) activity.  
     
     
         8 . The method of  claim 1  further comprising restoring genetic stability to said antibody-producing cell.  
     
     
         9 . The method of  claim 1  further comprising exposing said antibody-producing cell to a chemical mutagen.  
     
     
         10 . The method of  claim 1  wherein said antibody comprises an amino acid substitution with proline or hydroxyproline.  
     
     
         11 . The method of  claim 1  wherein said antibody comprises an amino acid substitution in a heavy chain variable region.  
     
     
         12 . The method of  claim 1  wherein said antibody comprises an amino acid substitution in a light chain variable region.  
     
     
         13 . The method of  claim 1  wherein said antibody comprises an amino acid substitution in a first framework region of a heavy chain.  
     
     
         14 . The method of  claim 13  wherein said substitution occurs at position 6 of a first framework region comprising the amino acid sequence of SEQ ID NO:18.  
     
     
         15 . The method of  claim 1  wherein said antibody comprises an amino acid substitution in a second framework region of a light chain.  
     
     
         16 . The method of  claim 14  wherein said amino acid substitution comprises proline or hydroxyproline.  
     
     
         17 . The method of  claim 15  wherein said substitution occurs at position 22 of a second framework region comprising the amino acid sequence of SEQ ID NO:21.  
     
     
         18 . The method of  claim 1  wherein said antibody comprises an amino acid substitution in a first framework region of a heavy chain and an amino acid substitution in a second framework region of a light chain.  
     
     
         19 . The method of  claim 17  wherein said amino acid substitution comprises proline or hydroxyproline.  
     
     
         20 . An antibody having enhanced effector function produced according to the method of  claim 1.