Methods for selective targeting

Abstract

A selective targeting method is disclosed comprising contacting a library of ligands, particularly a peptide library, with an anti-target to allow the ligands to bind to the anti-target; separating the non-binding ligands from the anti-target bound ligands, contacting the non-binding anti-target ligands with a target allowing the unbound ligands to bind with the target to form a target-bound ligand complex; separating the target-bound ligand complex from ligands which do not bind to the target, and identifying the target-bound ligands on the target-bound ligand complex wherein the target-bound ligands have a K D in the range of about 10 −7 to 10 −10 M. Additionally claimed are the ligands identified according to the method.

1 . A method for screening a peptide library comprising the steps of,
 (a) contacting the peptide library with an anti-target to allow the peptides to bind with said anti-target;   (b) separating unbound peptides;   (c) contacting the unbound peptides with a selected target to allow said unbound peptides to bind with the target to form a target-bound peptide complex;   (d) separating said target-bound peptide complex from peptides which do not bind to said target; and   (e) identifying the target-bound peptides on the target-bound peptide complex.   
     
     
         2 . The method according to  claim 1 , wherein step (a), (b), (c) or (d) is repeated between 2 to 10 times. 
     
     
         3 . A method for screening a peptide library comprising the steps of,
 (a) contacting the peptide library with a selected target and an anti-target essentially simultaneously to allow the peptides to bind with said target to form a target-bound peptide complex;   (b) separating the target-bound peptide complex from the anti-target, anti-target bound peptides and free peptides; and   (c) identifying the target-bound peptides on the target-bound peptide complex.   
     
     
         4 . The method according to  claim 3 , wherein said contacting step is in vivo. 
     
     
         5 . The method according to  claim 3 , wherein said contacting step is in vitro. 
     
     
         6 . The method according to  claim 1 , wherein the target-bound peptides bind with a selectivity corresponding to at least 10:1 and have a KD in the range of at least about 10-7 M. 
     
     
         7 . The method according to  claim 1 , wherein k off  is about 10 −4  sec −1  or less. 
     
     
         8 . The method according to  claim 1 , wherein the identifying step comprises amplifying a nucleic acid coding for the target-bound peptide in a polymerase chain reaction. 
     
     
         9 . The method according to  claim 3 , wherein the target-bound peptide is not released from the target during the identifying step. 
     
     
         10 . The method according to  claim 1 , wherein the peptides are fused to a phage coat protein. 
     
     
         11 . The method according to  claim 1 , wherein separating said target-bound peptide further includes an acid elution step. 
     
     
         12 . The method according to  claim 1 , wherein the identified target-bound peptides are less than 25 amino acids in length. 
     
     
         13 . The method according to  claim 1 , wherein the selectivity of the peptide binding affinity to the target compared to the peptide binding affinity to the anti-target is at least 20:1. 
     
     
         14 . The method according to  claim 1 , wherein the anti-target is skin or hair. 
     
     
         15 . The method according to  claim 1 , wherein the target is a cytokine selected from the group consisting of TNF and VEGF. 
     
     
         16 . The method according to  claim 1 , wherein the target is a stain. 
     
     
         17 . The method according to  claim 1 , wherein the target is a cell surface receptor. 
     
     
         18 . The method according to  claim 1 , wherein the target is a hematopoietic cell. 
     
     
         19 . The method according to  claim 1 , wherein the target is a protease enzyme and the anti-target is a different protease enzyme. 
     
     
         20 . (canceled) 
     
     
         21 . A peptide comprising the amino acid sequence of any one sequence of SEQ ID NOS: 3-17 or 79-102, or an amino acid sequence having at least 85% sequence identity thereto. 
     
     
         22 - 32 . (canceled)