ANTIBODIES SPECIFIC FOR UNGULATE PrP

Abstract

The present invention provides antibodies that specifically bind with a high degree of binding affinity to a native ungulate PrP C and/or a denatured ungulate PrP Sc , but not to a native ungulate PrP Sc . Preferred antibodies find native bovine PrP C and treated PrP Sc but not native bovine PrP Sc and can be used in an assay to determine if a sample is infected with infectious prions, i.e. PrP Sc .

1 .- 20 . (canceled)  
     
     
         21 . A method of detecting PrP Sc  in a sample, comprising the steps of: 
 treating a sample obtained from an ungulate to denature PrP Sc  in the sample;    contacting the sample with a labeled antibody characterized by its ability to bind to denatured ungulate PrP Sc  and native ungulate PrP C  with a binding affinity K a  of 10 8  l/mol or more; and to native ungulate PrP Sc  with a binding affinity K a  of 10 6  l/mol or less; and further characterized by not binding to PrP C  of a mammal other than an ungulate; and    detecting the labeled antibody bound to denatured ungulate PrP Sc .    
     
     
         22 . A method of detecting PrP Sc  in a sample, comprising the steps of: 
 treating a sample obtained from an ungulate to denature PrP Sc  in the sample;    contacting the sample with a labeled antibody characterized by its ability to bind to denatured bovine PrP Sc and native bovine PrP C  with a binding affinity K a  of 10 8  l/mol or more and to native ungulate PrP Sc with a binding affinity K a  of 10 6 l/mol or less; and    detecting the labeled antibody bound to denatured ungulate PrP Sc .    
     
     
         23 . A method of detecting PrP Sc  in a sample, comprising the steps of: 
 treating a sample obtained from an ungulate to denature PrP Sc  in the sample;    contacting the sample with a labeled antibody characterized by its ability to bind to denatured bovine PrP Sc  and native bovine PrP C  with a binding affinity K a  of 10 8  l/mol or more and to native bovine PrP Sc  with a binding affinity K a  of 10 6  l/mol or less and further characterized by not binding to PrP C  of a mammal other than an ungulate; and    detecting the labeled antibody bound to denatured ungulate PrP Sc .    
     
     
         24 . A method of detecting PrP Sc  in a sample, comprising the steps of: 
 treating a sample obtained from an ungulate to denature PrP Sc  in the sample;    contacting the sample with a labeled antibody which specifically binds to native ungulate PrP C , said antibody produced by the process comprising the steps of: synthesizing a library of antibodies on phage; panning the library against a sample by bringing the phage into contact with a composition comprising ungulate PrP proteins; isolating phage which bind native ungulate PrP C  wherein the antibody is characterized by its ability to bind to denatured ungulate PrP Sc  and native ungulate PrP C  with a binding affinity K a  of 10 8  l/mol or more and to native ungulate PrP Sc  with a binding affinity K a  of 10 6  l/mol or less; and analyzing the isolated phage to determine a sequence encoding an amino acid sequence to which the PrP C  binds.    
     
     
         25 . The method of  claim 24 , wherein the library of antibodies on phage are prepared by: immunizing a host mammal with PrP protein to create an immune response; extracting cells from the host mammal which cells are responsible for production of antibodies; isolating RNA from the cells of the host mammal; reverse transcribing the RNA to produce cDNA; amplifying the cDNA using a primer; and inserting the cDNA into a phage display vector such that antibodies are expressed on the phage.  
     
     
         26 . The method of  claim 24 , wherein the process further comprises: panning antibodies against an antigen dispersed in a liposome.  
     
     
         27 . The method of  claim 26 , wherein the antigen dispersed in a liposome is a peptide encoding an epitope of PrP C  that is not available on PrP Sc .  
     
     
         28 . The method of  claim 26 , wherein the antigen dispersed in a liposome comprises bovine residues 90-120.  
     
     
         29 . An assay, comprising: 
 a support surface; and    antibody characterized by its ability to bind to denatured ungulate PrP Sc  and native ungulate PrP C  with a binding affinity K a  of 10 8  l/mol or more; and to native ungulate PrP Sc  with a binding affinity K a  of 10 6  l/mol or less; and further characterized by not binding to PrP C  of a mammal other than an ungulate.    
     
     
         30 . The assay of  claim 29 , wherein the antibody is characterized by an ability to bind 50% or more denatured ungulate PrP Sc  in a liquid flowable sample.  
     
     
         31 . The assay of  claim 29 , wherein a plurality of different antibodies are bound to the support surface and each antibody has a K a  of 10 7  l/mole or more relative to PrP Sc .  
     
     
         32 . An assay, comprising: 
 a support surface; and    antibody characterized by its ability to bind to denatured bovine PrP Sc  and native bovine PrP C  with a binding affinity K a  of 10 8  l/mol or more and to native ungulate PrP Sc  with a binding affinity K a  of 10 6  l/mol or less.    
     
     
         33 . The assay of  claim 32 , wherein the antibody is characterized by an ability to bind 50% or more denatured ungulate PrP Sc  in a liquid flowable sample.  
     
     
         34 . The assay of  claim 32 , wherein a plurality of different antibodies are bound to the support surface and each antibody has a K a  of 10 7  l/mole or more relative to PrP Sc .  
     
     
         35 . An assay, comprising: 
 a support surface; and    antibody characterized by its ability to bind to denatured bovine PrP Sc  and native bovine PrP C  with a binding affinity K a  of 10 8  l/mol or more and to native bovine PrP Sc  with a binding affinity K a  of 10 6  l/mol or less and further characterized by not binding to PrP C  of a mammal other than an ungulate.    
     
     
         36 . The assay of  claim 35 , wherein the antibody is characterized by an ability to bind 50% or more denatured ungulate PrP Sc  in a liquid flowable sample.  
     
     
         37 . The assay of  claim 35 , wherein a plurality of different antibodies are bound to the support surface and each antibody has a K a  of 10 7  l/mole or more relative to PrP Sc .