HISTOCHEMICAL-LOCALIZATION OF SIALYLATED GLYCOCONJUGATES WITH TRITRICHOMONAS-MOBILENSIS LECTIN (TLM)

A new sialic acid-specific lectin from the colonic parasite of squirre l monkeys Tritrichomonas mobilensis (TML) was tested on human and mous e tissues for histochemical staining properties. There were no substan tial differences in reactivity between frozen and formalin fixed paraf fin sections, TML staining was blocked by preincubation with sialic ac id or by sialidase digestion. TML/anti-TML antibody histochemistry was identical with the TML-gold technique. The staining pattern was not b lood group dependent. TML stained strongly the luminal membranes of no rmal vascular endothelium as well as endothelial neoplasms. Lymphatic vessels and capillaries of kidney glomeruli and lung alveolar septi we re negative or only slightly positive, In parenchymatous organs lumina l membrane positivity was dominant, preferably of cells lining ducts, Weak fine-granular cytoplasmic and basolateral membrane staining was a lso observed. Umbrella cells in transitional epithelium and basal laye rs of squamous epithelia showed strong reactivity with cell membranes. Mucin in respiratory epithelium was positive whereas gastrointestinal mucins failed to stain uniformly. Erythrocytes and most white blood c ell types showed distinct membrane positivity. Acetylation or alkaline O-deacetylation of tissue sections did not substantially change TML r eactivity. Oxidation, however, completely blocked TML staining except for respiratory epithelium and colonic mucin.