Efficient lentiviral transduction of primary human acute myelogenous and lymphoblastic leukemia cells

Background and Objectives. Gene manipulation and cell vaccines represent in novative strategies to enhance the immunogenicity of cancer cells. We adopt ed a defective lentivirus derived from the human immunodeficiency virus (HI V)-1 backbone and carrying the enhanced green fluorescent protein (EGFP) ge ne to transduce primary human acute myelogenous leukemia (AML) and B-precur sor acute lymphoblastic leukemia (ALL) cells. Design and Methods. AML blasts were maintained with or without cytokines (s tem cell factor, FLT3 ligand and interleukin 3) for 48 hours, and successiv ely infected with two spin infection cycles, ALL blasts were cultured on a murine S17 stromal cell line. Results. As regards AML cells, the efficiency of infection at 7 days varied from 8.4 to 37%, As confirmed by cell cycle analysis, cells were, in most of the cases, blocked in different phases of the cycle and did not prolifer ate during culture: the infection was therefore obtained in the absence of cell proliferation. In contrast, the maintenance of optimal cell viability was of fundamental importance for obtaining good infection levels. As regar ds ALL blasts, the percentages of infection after 3 days varied from 4.4 to 21%. Interpretation and Conclusions. These preliminary data suggest that gene de livery into primary human AML and B-precursor ALL cells by an HIV-1 derived lentiviral vector could represent a strategy for engineering leukemic cell s for use as cancer vaccines. (C) 2001, Ferrata Storti Foundation.