USE OF FLUORESCEIN-CONJUGATED BANDEIRAEA-SIMPLICIFOLIA B4-ISOLECTIN AS A HISTOCHEMICAL REAGENT FOR THE DETECTION OF ALPHA-D-GALACTOPYRANOSYL GROUPS - THEIR OCCURRENCE IN BASEMENT-MEMBRANES

The Bandeiraea simplicifolia B4-isolectin, which combines specifically with α-d-galactopyranosyl groups, has been conjugated with fluorescein isothiocyanate and demonstrated to be a reliable histochemical probe for the detection of these groups in normal tissues of mouse, rabbit, rat and man. Specificity of binding of the fluorescein-conjugated B. simplicifolia B4-isolectin to native cryostat tissue sections was demonstrated in two ways: 1. 1. The hapten inhibitor methyl α-d-galactopyranoside prevented the binding of the lectin to tissues whereas the non-hapten methyl α-d-glucopyranoside did not. 2. 2. Pretreatment of tissue sections with coffee bean α-galactoside abolished lectin binding whereas pretreatment with A. niger or E. coli β-galactosidase did not. The fluorescein-conjugated isolectin visualized α-d-galactopyranosyl groups in basement membranes and on the surface of certain epithelial cells of mouse, rat, rabbit, and on the surface of the TA3 murine mammary carcinoma. These studies suggest that the B. simplicifolia B4-isolectin may be of great utility in studying the family of α-d-galactosyl-containing glycoconjugates of basement membranes in pathological states accompanied by basement membrane changes, such as diabetes mellitus, and in neoplasms that secrete basement membrane. © 1979.