Immunogold-silver staining of mesangial antigen in lowicryl K4M- and LR gold-embedded renal tissue using epipolarization microscopy.

We examined the localization of a glomerular mesangial antigen with a Thy-1.1 monoclonal antibody by epipolarization microscopy (EPI) of silver-enhanced, immunogold-stained renal tissue embedded in LR Gold and Lowicryl K4M, and compared the attributes of these hydrophilic resins. Antigen was well preserved in tissue embedded in both resins. LR Gold-embedded tissue demonstrated excellent immunostaining properties, sectioned more easily, and showed better durability during staining than K4M. Lowicryl K4M-embedded tissue, however, displayed a phenomenon of self-illumination when counterstained with eosin which was not seen with LR Gold. This enabled immunostaining to be precisely related to tissue morphology without the necessity of simultaneous transillumination, which can be problematic when used in combination with EPI because of reflection of incident illumination from sub-stage optical surfaces.