Chimeric antibody (A), derived from the monoclonal antibody P3, which recognizes N-glycosylated gangliosides and is produced by hybridoma ECACC 94113026, is new. Chimeric antibody (A), derived from the monoclonal antibody P3, which recognizes N-glycosylated gangliosides and is produced by hybridoma ECACC 94113026, has the following complementarity determining regions (CDR); for heavy chain: CDR1 (RYSVH); CDR2 (MIWGGGSTDYNSALKS) and CDR3 (SGVREGRAQAWFAY), and for the light chain: CDR1 (KASQDVSTAVA); CDR2 (SASYRYT) and CDR3 (QQHYSTPWT). Independent claims are also included for the following: (1) cell lines that produce (A); (2) chimeric monoclonal antibody (A') derived from the monoclonal antibody 1E10, which recognizes P3 and is produced by ECACC 97112901, having the CDRs: heavy chain: CDR1 (SYDIN); CDR2 (WIFPGDGSTKYNEKFKG) and CDR3 (EDYYDNSYYFDY), and light chain: CDR1 (RASQDISNYLN), CDR2 (YTSRLHSG), and CDR3 (QQGNTHPWT); and (3) cell lines that produce (A'). ACTIVITY : Cytostatic. No relevant biological data given. MECHANISM OF ACTION : Induction of a specific immune response. No relevant biological data given.