Immunohistochemical staining on cryosections of colon tissue using 8G5. PBS containing 2.5% horse serum served as negative control (A). Detection of 8G5 occurred with a bioti-nylated anti-mouse-IgG secondary antibody and a streptavidin-peroxidase conj ugate (B). Diaminoben-zidine was used as substrate. Nuclei were stained with hematoxilin.