COMPARISON OF 7 BIOLUMINESCENT AND CHEMILUMINESCENT REAGENTS FOR IN-SITU DETECTION OF ANTIGENS AND NUCLEIC-ACIDS

Bio- and chemiluminescence have proved sensitive enough to compete wit h chromogenic and radioisotopic tracers for in situ detection. However , they must also provide a discriminant morphological analysis of the specific signal. We have tested seven bio- or chemiluminescent reagent s for tissue antigen and nucleic acid detection by immunocytochemistry (ICC) or in situ hybridization (ISH). They were based on luminescent detection of peroxidase, alkaline phosphatase, beta-galactosidase or x anthine oxidase. We also explored whether high molecular weight polyme rs could increase the spatial definition of the photon emission.An ICC D camera was used to collect the light signal provided by immunolabell ing of endothelial cells and by ISH of human papilloma virus on cell s mears. Among the enzyme-luminescent substrate combinations tested, the enhanced luminol chemiluminescence (ECL) gave the best resolution of the specific signal. The other systems were mainly hampered by a high diffusion of the reaction product over the tissue section. Unfortunate ly, in this case, the high molecular weight polymers tested were ineff icient. However, the addition of polyvinylalcohol (PVA) or polyvinylpy rrolidone (PVP) significantly improved respectively the definition and intensity of ECL photon emission. We demonstrate that chemiluminescen ce gives a morphological resolution allowing histological examination. The extension of this new application, now depends on physicochemical adaptation of chemiluminescent reagents to the constraints of tissue detection.