Abstract: The present invention relates to immunotherapy strategies for the treatment of malignancies. The present immunotherapy strategies have gangliosides as a target. Gangliosides are glycosphingolipids which are present on normal cells and on malignant cells. On malignant cells they are more abundant and expressed in a different organization and conformation. The present invention provides antibodies which recognize these gangliosides, which antibodies are specific, have recurrent idiotypes and have value as immunoregulators. The invention further provides anti-idiotypic antibodies against anti-ganglioside antibodies. These are useful in vaccination strategies.