Improvement of the glucose oxidase immunoenzyme technic. Use of a tetrazolium whose formazan is stable without heavey metal chelation.

Glucose oxidase immunoenzymatic localization provides a simple way to show antigens in mammalian tissues, with no need for the quenching of endogenous nonspecific staining. The method is useful for the demonstration of many antigens in formalin-fixed, paraffin-embedded tissues. Improvement of this technic by the use of p-nitro blue tetrazolium chloride (NBT) as the disclosing reagent provides a stable, finely grained localization not possible with the previously used thiazolyl blue (MTT). The described modification makes available an ideal immunoenzymatic stain for the study of tissues at the level of the light microscope. This stain is especially useful for the examination of tissues with hemorrhagic or inflammatory lesions, since there is no endogenous background staining. Slides are permanent, and the technic can be used with peroxidase-labeled antibody to localize two antigens in the same tissue.