The present invention provides MHC Class II restricted melanoma antigens recognized by CD4.sup.+ T cells. This invention further provides prophylactic and therapeutic applications for the Class II restricted melanoma antigens. In particular, this invention provides tyrosinase Class II restricted melanoma antigens, as well as tyrosinase immunogenic peptides which have been modified to enhance their immunogenicity. These antigens can serve as an immunogens or vaccines to prevent or treat melanoma. In addition a method for isolating Class II restricted melanoma antigens or identifying new Class II restricted melanoma antigens is provided.