1. An isolated peptide which binds to a member of EphB1 or EphB2 receptor and inhibits binding of Ephrin B ligand to said member of the EphB1 or EphB2 receptor, wherein said peptide consists of less than 25 amino acid residues and has the amino acid sequence of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, or SEQ ID NO: 5.