Leukemia cells genetically modified to express immunomodulators such as CD80 have been shown to stimulate the ex vivo proliferation of human autologous anti-leukemia reactive T cells and induce a protective effect against leukemia challenge in animal models in vivo. These results led us to further characterize the effect of other immunostimulatory genes that, when co-expressed by leukemia cells, may further enhance the antigen presentation through MHC class 1 and class 11 pathways. It was recently shown that second generation HIV-derived lentiviral vectors (lacking vpr, vpu, vif and nef) expressing CD80 and/or GMCSF can efficiently transduce primary Acute Myeloid Leukemia (AML) and Acute Lymphocytic Leukemia (ALL) cells (40-100% CD80 positive) and promote stable and high levels of expression (Blood. 2000; 96:1317-1326). In the present studies, we have evaluated a safer, third generation self-inactivating HIV vector system (lacking tat and the original HIV LTR), kindly provided by L. Naldini et al (University of Torino, Italy), to deliver GMCSF, CD80, IL-4 and CD40L into leukemia cells. The produced vectors were concentrated to high titers (10E8 particles/ml) and successfully expressed the transgenes, as assayed by F ACS (CD80, CD40L) and EL1SA (GM-CSF, IL-4). Primary leukemia cells transduced with third generation vectors will be used to stimulate autologous effector cells obtained from AML patients during remission in Mixed Lymphocyte Reactions (MLR). The autocrine and paracrine effects of the expression of the transgenes on antigen presentation in AML cells will be also evaluated. Finally, the lentivirally transduced AML are expected to provide a potent activation of T-, B- and dendritic cells that can be explored for ex vivo expansion of autologous anti-AML effector cells and for clinical vaccination procedures.
|Original language||English (US)|
|Issue number||11 PART II|
|State||Published - Dec 1 2000|
ASJC Scopus subject areas
- Cell Biology