Transfer and expression of the human interleukin-4 gene in carcinoma and stromal cell lines derived from lung cancer patients

Introduction of the interleukin-4 (IL-4) gene into cells derived from human tumor tissue provides a means for generating a specific tumor vaccine. Such a vaccine could be produced by either transducing tumor-derived stromal cells with the IL-4 vector and coinjecting tumor cells, or by transducing the tumor cells themselves. We have developed a protocol for culturing cells from non-small cell lung tumors and routinely produce tumor cultures from 25% of tumors, and stromal cultures from > 80% of specimens. Several of these cultures were transduced with the incompetent retroviral vector G1NaSvi4.25, which encodes the human IL-4 cDNA and the G418-resistance gene. Infection of cells by viral titers of 2-5 x 10(4) plaque-forming units/ml, and a multiplicity of infection of 0.1:1 to 1:1 yielded transfer efficiencies of 3.3-32.0 transfectants per 10(4) cells in six of eight attempts. Following selection with the neomycin analog G418, IL-4-producing cells were isolated. IL-4 titers ranged from 142 to 593 U/ml/10(6) in a 24-h collection. Successful transfer of the IL-4 gene was demonstrated by polymerase chain reaction amplification of cDNA derived from reverse-transcribed total RNA, by immunohistochemistry, and by enzyme-linked immunosorbent assay. The IL-4-producing cells were shown to stimulate the proliferation of autologous peripheral blood lymphocytes in one individual by 7.5-fold over control and by 4.1-fold over non-IL-4 producing tumor cells.