IN-VITRO TARGETING AND SPECIFIC TRANSFECTION OF HUMAN NEUROBLASTOMA-CELLS BY CHCE7 ANTIBODY-MEDIATED GENE-TRANSFER

We developed a new vector for gene targeting of neuroblastoma (NB) cel ls, based on the utilization of a mono clonal antibody (chCE7) covalen tly linked to polylysine (PL). In the presence of chloroquine, chCE7-P L-DNA complexes transfected NB cells as efficiently as DOTAP, transfec tam, TF-X50 or lipofectamine. This was demonstrated by transfection of the luciferase or beta-galactosidase reporter genes in three differen t NB cell lines. This transfection was specific, since it was inhibite d in the presence of competing unconjugated chCE7 antibody (Ab), and w as not observed in cell lines negative for the CE7 antigen. We tested the potential biological activity of a plasmid coding for gamma-interf eron (gamma IFN) transfected with chCE7-PL. HLA ABC expression on NB c ells was induced after transfection with pCMV-gamma IFN at a higher le vel than after incubation with 1000 IU/ml of purified gamma IFN. Moreo ver, these HLA ABC-positive NB cells were able to activate autologous cytotoxic T lymphocytes in vitro. Thus chCE7-PL is able to target a pl asmid to NB cells and to allow the expression of the transfected gene in a biologically active form.