Usage of Aplysia lectin interactions with T antigen and poly-N-acetyllactosamine for screening of E-coli strains which bear glycoforms cross-reactingwith cancer-associated antigens

Aplysia gonad lectin (AGL), which strongly agglutinates cancer cells. was f ound, in the present study, to bind to erythrocyte T antigen, in addition t o its affinity to Ii system antigens. These antigens were reported to be ov erexpressed and to contribute to tumor progression and invasion. In healthy human sera, there an antibodies against them. stimulated by the normal int estinal microflora. which bear similar glycoforms. Since the levels of thes e antibodies were reported to be lower in most cancer patients' sera, we ha ve examined the applicability of AGL to isolation of enteric commensal Esch erichia coli strains which bear glycoforms cross-reacting with the cancer-a ssociated antigens. Among 30 E. coli isolates examined, two were agglutinat ed by AGL. One of them was also agglutinated by certain related galactophil ic lectins, which bind to the T and Tn antigens. The agglutination of the t wo bacteria by healthy human sera, as a group, was stronger than that displ ayed by the cancer patients' sera. These results indicate that AGL might be useful for identification of the desired bacteria, which could potentially serve for cancer diagnosis and therapy. (C) 2001 Federation of European Mi crobiological Societies. Published by Elsevier Science B.V. All rights rese rved.