REPORTS Possible Role of Human Natural Anti-Gal Antibodies in the Natural Antitumor

face residues has been correlated with the metastatk potential of murine tu-mor cells. We report that Galal-3Gal residues are expressed at the cell sur-face of malignant human cancer cells, including four cell lines and 50 % of the malignant breast specimens ob-tained by aspiration biopsy. In con-trast, all benign breast biopsies and normal cells were GaIal-3Gal nega-tive. Affinity-purified anti-a-galactosyl IgG (anti-Gal) antibody, which specif-ically recognizes Galal-3Gal residues, significantly inhibited cell attachment in two in vitro assays thought to indi