Patent ID: 7294753

Claim:
A method of preparing a high-affinity anti-migration inhibitory factor (anti-MIF) antibody or fragment thereof comprising the steps of: (a) preparing a transgenic mouse in which both alleles of the endogenous genes encoding a MIF protein are functionally knocked out by a method comprising (i) introducing a MIF-targeting construct into a mouse embryonic stem (ES) cell; (ii) introducing the modified mouse ES cell into a mouse embryo; (iii) transplanting the modified embryo into a pseudopregnant mouse; (iv) allowing said modified embryo to develop to term; and (v) identifying a transgenic mouse with germ cells in which at least one allele of the endogenous MIF gene is functionally knocked out; and (vi) breeding the transgenic mouse of step (v) to obtain a transgenic (MIF −/− ) mouse in which both alleles of the endogenous MIF genes encoding said MIF protein are functionally knocked out; (b) immunizing said transgenic mouse with a MIF protein or a polypeptide fragment thereof; and (c) obtaining a high affinity anti-MIF antibody or fragment thereof from said animal.