DEVELOPMENT AND IN-VITRO CHARACTERIZATION OF A GM-CSF SECRETING HUMANOVARIAN-CARCINOMA TUMOR VACCINE

A human ovarian carcinoma cell line (UCI-107) was genetically engineer ed to secrete the cytokine granulocyte-macrophage colony stimulating f actor (GM-CSF), by retroviral medicated gene transduction. This line w as transduced with the LXSN retroviral vector containing the human GM- CSF gene and the neomycin resistance selection marker. Numerous GM-CSF secreting clones were randomly isolated and one clone, termed UCI-107 M GM-CSF-MPS, extensively characterized. This clone was shown to const itutively secrete high levels of GM-CSF (ie 420-585 pg ml(-1) 10(5) ce lls(-1) 48 h(-1)) for over 35 passages and 6 months of study. Like the parental cell line UCI-107, UCI-107M GM-CSF-MPS cells expressed MHC c lass I and Her2/Neu surface antigens but did not express detectable MH C class II, ICAM-1 or CA-125. No change in the expression of these sur face proteins was noted between the parental cells and this GM-CSF sec reting clone. The morphology of UCI-107M GMCSF-MPS did not differ from that of the parental or LXSN vector control cells; however, parental cells had a slightly faster growth rate than the transductants. UCI-10 7M GM-CSF-MPS was sensitive to gamma irradiation, since as little as 2 500 rads killed the cells within 10 days of irradiation. However, even after higher doses of irradiation (ie 10 000 rads), GM-CSF secretion continued in vitro until about day 8. Interestingly, irradiation induc ed up-regulation of the surface antigens previously expressed, and the y remained up-regulated for as long as the cells remained viable. The potential use of these GM-CSF secreting ovarian carcinoma cells as vac cines for women with advanced ovarian cancer will be discussed.