Generation of human monoclonal antibodies against ganglioside antigens and their applications in the diagnosis and therapy of cancer.

Different approaches to generating human monoclonal antibodies (MAbs) against tumor-associated ganglioside antigens have been carried out in several laboratories. A specific goal addressed by our laboratory is to produce human MAbs to several ganglioside antigens of relevance as therapeutic targets, such as the GM2, GD2, GD3 and GM3 gangliosides in melanoma. In vitro immunization of human B lymphocytes from normal donors was performed using liposomes containing gangliosides as the immunizing antigen combined with either complete tetanus toxoid or a synthetic peptide corresponding to a T helper epitope to stimulate in vitro immunization. Specific human anti-ganglioside antibodies were obtained, indicating that the antibody response found in vitro was antigen-driven. To overcome the widely reported problems concerning stability of immunoglobulin production by the antibody-secreting cell lines, a method of positive selection using GM3-coated magnetic beads has been developed in order to rescue unstable clones. Development of new methods to reproducibly generate ganglioside-specific human MAbs will amplify the possibilities for diagnostic and therapeutic applications.