We are investigating the feasibility and potential utility of post-remission vaccination with genetically-modified autologous AML cells. Our strategy focuses on the use of adenoviral vectors to deliver cDNAs encoding costimulatory molecules to leukemic blasts. Although AML cells have previously been reported to be resistant to adenoviral gene transfer, recent reports suggest that low infection efficiencies may be overcome by the addition of polycationic transfection adjuvants such as polyamidoamine dendrimer. To facilitate AML vaccine production for an ongoing clinical trial, we have carefully optimized adenoviral infection conditions. We report here the use of a virus polycation complex (VPC) to enhance adenoviral infection efficiency. We analyzed 14 AML patients (comprising a variety of FAB types, as well as both newly diagnosed/relapsed, and primary/secondary AML samples) with high peripheral blood blast counts (mean 71%). Following density gradient separation, cells were infected in parallel under standardized conditions (MOI 300, 48 hrs., no growth factors) with the CD80 expressing vector AdMhBV. 1, either using virus alone, or with the virus delivered as part of a polyamidoamine dendrimer-based VPC. Blast infection efficiency (CD80 expression) was then determined flow cytometrically, as were the expression of the coxsackievirus and adenovirus receptor (CAR) and of the integrins αvβ3/αvβ5 (before transfection), which are required for viral attachment and internalization. We report that the efficiency of adenoviral infection with VPC exceeded that of vector alone (37% vs. 21%, P<0.01). However, primary AML samples (n=9) could be infected more efficiently than could secondary AML samples (n=5) (53% vs. 9.5%, with VPC), with the highest infection efficiencies (87% and 86%) being observed in two newly diagnosed primary AML samples that expressed both CAR and αvβS (>2-fold shift in mean fluorescence, relative to isotype control). Indeed, overall infection efficiencies correlated strongly (P<0.01 in all cases) with CAR and αvβ5 expression, both with and without the use of VPC. We conclude that AML cells can be infected efficiently with adenoviral vectors (particularly with the use of VPC), and that the levels of CAR and αvβ5 expression may be predictive of individual efficiency.
|Original language||English (US)|
|Issue number||11 PART II|
|State||Published - Dec 1 2000|
ASJC Scopus subject areas
- Cell Biology