A FLUORESCENCE METHOD FOR THE VISUALIZATION OF INFLAMMATORY CELLS IN INTESTINAL-MUCOSA

Treatment of paraffin or cryostat sections from rat, rabbit and man, with fluorescein isothiocyanate (FITC) in buffer (1 μg/l), resulted in visualization of highly fluorescent leukocytes with a granular staining in light mocroscopy. FITC staining of paraffin-embedded colonic tissue was compared with three other staining methods, i.e, (1) FITC-conjugated anti-neutrophil antibodies, (2) endogenous peroxidase with 3,4-diaminobenzidine, and a (3) FITC-conjugated Lotus tetragonolobus lectin. Good correlations between FITC staining and the three other methods were found (r:0.97, 0.98 and 0.98; P < 0.001). Inhibition of receptors for the FITC conjugates prior staining, by preincubation with unconjugated anti-neutrophil antibodies or L-fucose, abolished the staining with antibodies and lectin. This study shows that staining with unlabeled FITC represents a quick and convenient method for the estimation of phagocytic cells (polymorphonuclear cells and macrophages) in histological specimens. © 1990.