Post-remission vaccination with genetically-modified autologous AML cells has been proposed as one approach to the management of minimal residual disease. We have focused on the use of adenoviral vectors to generate such vaccines. While optimized culture and infection conditions, and the addition of hematopoietic growth factors and transfection adjuvants have improved our ability to infect primary AML cells, there still exists marked variability in infection efficiency among samples. Adenovirus entry requires the fibre proteinmediated attachment to the coxsackievirus and adenovirus receptor (CAR), as well as a penton base protein-dependent interaction with integrin avβ3 or avβS, leading to internalization. To elucidate whether the observed variability in adenoviral infection efficiency could be related to the expression of these receptors, we attempted to correlate the expression of CAR, avβ3, and ctvβS by the purified blasts from 15 patients with AML of various FAB types, with adenoviral infection efficiency. Receptor expression by density gradient purified blasts was measured flow cytometrically using the MAbs RmcB, LM609, and P1F6. In parallel, cells were infected with the CD80-expressing vector AdMhB7.1 (MOI 300, without added growth factors or transfection adjuvants), and CD80 expression was determined by FACS. We report that adenoviral infection efficiency correlates directly with the levels of CAR and <xvβ5 expression (P<0.05 and <0.001). Specifically, the mean infection efficiency of CAR positive samples was 65% compared to 10% for CAR negative samples, while the corresponding efficiencies for avβS positive and negative blasts were 24 % and 5%. Notably, the two patients demonstrating the highest blast infection efficiencies (83% and 71 %) expressed both CAR and avβS. In contrast, infection efficiency was unrelated to levels of avβS expression. Current optimized AML blast adenovirus infection strategies require both a high MOI and the addition of hematopoietic growth factors and transfection adjuvants. We suggest that the measurement of blast CAR and ocvβS expression may allow adenoviral infection strategies to be individually tailored, by identifying those cases in which a high MOI and other culture/transfection additives are not required.
|Original language||English (US)|
|Issue number||11 PART II|
|State||Published - Dec 1 2000|
ASJC Scopus subject areas
- Cell Biology