Validation of RNA Aptamer Probes to Image Candida albicans in Paraffin-Embedded Sections of Wistar Rat Tongue

This study aimed to validate the use of Ca-apt-1, an RNA aptamer, that we generated previously as a probe for immunostaining of Candida albicans in rat tongue paraffin-fixed tissue sections MATERIAL AND METHODS: The performance of Ca-apt-1 as a detector molecule was compared with that of anti-C. albicans polyclonal antibody (PcAb), which was used as a positive control. Immunostaining images were visualized by light microscopy and were analyzed by using ImageJ software. Microscopic results demonstrated that Ca-apt-1 specifically recognized and immunostained C. albicans cells of rat tongue candidiasis, with a specificity comparable to that of PcAb. ImageJ analysis showed that the area (pixels) detected by Ca-apt-1 was wider than that detected by the antibody. This indicates that the binding affinity of Ca-apt-1 toward C. albicans was better than that of PcAb on paraffin-embedded tissues. This study demonstrates that Ca-apt-1 can be used as a probe for immunostaining of fixed tissue sections for oral candidiasis diagnosis.