DIFFERENTIAL EFFICACY OF ADENOVIRAL MEDIATED GENE-TRANSFER INTO CELLSFROM HEMATOLOGICAL CELL-LINES AND FRESH HEMATOLOGICAL MALIGNANCIES

As a first step to evaluate the possibility of gene therapy using aden oviral vectors in hematological malignancies in vivo, we tested the ef ficacy of gene transfer by a recombinant adenovirus in cell lines and fresh cells from various hematological neoplasms. Thirteen cell lines and samples from 27 patients were studied. Cells were infected by a re combinant adenovirus expressing beta galactosidase gene (Ad RSV betaga l) and efficacy of transduction assessed by evaluating betagal express ion in cells with a histochemical method. After infection of the cells at a multiplicity of infection (MOI) of 200 p.f.u./cell, the percenta ge of betagal-positive cells after 48h was high in two cell lines. K56 2 (64%) and RPMI 8226 (a myeloma cell line, 65%), relatively large in the two myeloma cell lines tested (41% and 20%, respectively) and in M T4 (an adult T cell leukemia cell line, 38%) and low or absent in othe r cell lines. In fresh samples from AML, ALL, CLL, NHL, myeloma and MD S, no betagal positive cells were seen 48h and 72h after infection, ex cept in one case of myeloma and one case of CLL (where 10% and 2% of b etagal positive cells were seen after infection, respectively). Exposu re of fresh malignant cells to GM-CSF before and during adenoviral inf ection, in three cases, did not increase the number of transfected cel ls. This suggests that adenoviral vectors, at least in their present f orm, cannot efficiently be used for direct gene transfer in hematologi cal malignant cells.