The present invention relates to new monoclonal antibodies and fragments of these antibodies, which have dual specificity and high affinity for N-acetyl GM3 and N-glycolyl GM3 and do not recognize other gangliosides. In another aspect, the present invention relates to the use of these antibodies and their fragments in the therapy of tumors characterized by a significant expression of any of the two antigens recognized by these antibodies, or a mixed expression of both antigens. Likewise, the invention relates to the use of these antibodies in the diagnosis of tumors expressing at least one of the two variants of the GM3 ganglioside.本發明係關於一種新穎單株抗體及這些抗體之片段，彼等對N-乙醯基GM3及N-羥乙醯基GM3具有雙重專一性及高親和力，且不會辨識其他神經節苷脂類。在另一態樣中，本發明係關於這些抗體及其片段於治療腫瘤的用途，該腫瘤特徵為大量表現這可被這些抗體辨識的二種抗原中之任一者或混合表現兩者抗原。同樣地，本發明係關於這些抗體在診斷表現這二種GM3神經節苷脂變異體類中至少一者之腫瘤的用途。
