IMMUNOCYTOCHEMICAL DETECTION OF CANDIDA-ALBICANS IN FORMALIN-FIXED, PARAFFIN-EMBEDDED MATERIAL

Aim-To assess the ability of the commercially available monoclonal ant ibody 1B12 (BioGenex, San Ramon, USA) to identify C albicans in formal in fixed, paraffin wax embedded material (FFPE). Methods-Broth culture s of 20 strains of seven Candida species were resuspended in 4% agaros e blocks, fixed in formalin for 24 hours, and embedded in paraffin wax . In addition, 16 blocks of FFPE tissue known to contain periodic acid -Schiff positive fungal hyphae were examined. Antigen retrieval involv ed microwave treatment of specimens in citrate buffer (0.01 M; pH 6.5) before addition of 1B12 antibody for 24 hours. Bound antibody was sub sequently detected using a biotinylated link antibody and a peroxidase conjugated streptavidin. Results-Only C albicans strains were 1B12 po sitive in the agarose blocks. All FFPE tissue blocks were found to con tain 1B12 positive hyphal structures, indicating the presence of C alb icans. Conclusions-The ability to identify candida organisms penetrati ng the lesional tissue in cases of chronic hyperplastic candidosis wil l help to clarify the role of individual Candida spp in this important form of oral candidosis.