Engineering of an anti-steroid antibody: amino acid substitutions change antibody fine specificity from cortisol to estradiol.

Immunoassays are widely used for determination of the concentration of steroid hormones. However, obtaining specific anti-steroid monoclonal antibodies remains difficult. We used antibody engineering and phage display methods to change the specificity of an anti-cortisol monoclonal antibody towards estradiol. This work demonstrates that production of recombinant antibodies may be a valuable way of obtaining the high-specificity antibodies required for steroid immunoassays.