Patent ID: 7537932

Claim:
A purified antibody, or binding fragment thereof, wherein the antibody or fragment specifically binds to a Flt3 ligand protein which binds to a Flt3 receptor, wherein said protein has the following physical characteristics: a) said protein migrates as an approximately 30 kD glycoprotein on SDS-Polyacrylamide gel electrophoresis under reducing conditions; b) said protein precipitates in ammonium sulfate at 60 to 85% saturation at 4° C.; c) on hydrophobic interaction chromatography with an (NH 4 ) 2 SO 4 gradient in 20 mM Tris, pH 7.5 on a Phenyl-5PW column, said protein elutes between 900-750 mM (NH 4 ) 2 SO 4 ; d) on anion exchange chromatography (NaCl gradient in 20 mM Tris, pH 7.5 on Mono Q column), said protein elutes between 130-250 mM NaCl; e) on cation exchange chromatography (NaCl gradient in 10 mM citrate, pH 3.0 on Mono S column), said protein elutes between 440-540 mM NaCl; f) on gel filtration chromatography (Sephacryl S200 column), said protein runs with an apparent molecular weight of 70 kD; g) on reversed phase HPLC (water to acetonitrile gradient in 0.1% TFA on a Poros R/H column), said protein elutes between 32-35% acetonitrile; and h) said protein comprises a sequence selected from the group consisting of: i) Phe Val Gin Thr Asn Ile Ser His Leu Leu Lys (SEQ. ID No. 1); ii) Asp Tyr Pro Val Thr Val Ala Val Xaa Leu Gin Asp Glu (Residues 1-13 of SEQ. ID No. 2); and, iii) Trp Ile Glu Gln Leu Lys (Residues 1-6 of SEQ. ID No. 4).