The invention essentially relates to the production of less immunogenic immunoglobulins by means of genetic engineering and, more specifically, to a monoclonal antibody recognizing antigens which contain the N-glycolil GM3 ganglioside but not other gangliosides of the N-glycolil or N-acetyl type, or the sulphated glycolipids. In particular the invention relates to peptides sequences encoding a recombinant monoclonal antibody against the N-glycolil GM3 ganglioside, or derivative fragments of the same. The invention further relates to pharmaceutical compositions containing the aforementioned antibody or fragments thereof and to the diagnostic or therapeutic use of same for breast cancer and melanoma.
