Identification of cryptosporidium in paraffin-embedded tissue sections with the use of a monoclonal antibody.

Recently a monoclonal antibody has been developed against the oocyst form of Cryptosporidium species for use in detecting the organism in fecal material. The authors undertook this study to determine if this antibody could be used in identifying Cryptosporidium species in paraffin-embedded tissue sections. Three biopsies showing Cryptosporidiosis as diagnosed by characteristic appearance by light and electron microscopy were selected from the surgical pathology files at the authors' institution. Paraffin sections were examined with the use of both an indirect immunofluorescence and an avidin-biotin-peroxidase technique. In all the cases, prominent staining of oocysts was seen; however, intracellular trophozoites did not react with the antibody. The authors conclude that this antibody can be used to identify Cryptosporidium species oocysts in tissue sections and that the antibody appears to be specific for the oocyst form only.