Figure 4 .

Indirect immunofluorescence of human duodenum. The photomicrograph using mouse antihuman MUC3 mucin antibody as the primary antibody is shown. The cross section view of a villus from a biopsy taken from the second part of the duodenum shows fluorescence of the epithelial cell cytoplasm with increased fluorescence at the surface of the epithelial cells (arrows). Controls using preimmune serum, FITC conjugate alone, and phosphate buffered saline were negative (not shown). Magnification 40×.