Adenovirus vector-induced inflammation:: Capsid-dependent induction of the C-C chemokine RANTES requires NF-κB

Adenovirus vectors for gene therapy activate responses in the host that result in acute inflammation of transduced tissues. Our previous studies in vivo demonstrate that chemokines, including the C-C chemokine RANTES (regulated on activation, normal T cell expressed and secreted), contribute to the acute inflammation induced by adenovirus vectors. Various first-generation adenovirus vectors, including adCMVbetagal, were equally capable of inducing the expression of RANTES 3 hr after transduction in epithelial HeLa and REC cells. Deletional analysis of the human RANTES promoter revealed that induction by adCMVbgal required the elements spanning base pairs 290 to 225 of the gene. Electrophoretic mobility shift assays demonstrated that nuclear extracts from adCMVbetagal-transduced HeLa cells bound to an NF-kappaB site at position -54. Overexpression of I-kappaBalpha suppressed adCMVbetagal induction of RANTES, confirming that this process was dependent on the nuclear translocation of NF-kappaB. The coxsackievirus-adenovirus receptor (CAR)-independent, serotype 3 adenovirus was equally capable of inducing the expression of RANTES in HeLa cells. This observation suggested that binding to CAR was not specifically required in adenovirus vector-induced RANTES expression. The use of RGD peptides to block adCMVbetagal interactions with alpha(v)-integrins reduced RANTES expression but also transduction efficiency. In CAR-deficient P815 cells, binding of adCMVbetagal to alpha(v)-integrins without efficient cell transduction did not result in increased RANTES expression. Expression of human CAR in P815 cells increased the binding and transduction efficiency of adCMVbetagal and resulted in RANTES expression in these cells. These results suggest that the induction of RANTES by adenovirus vectors is dependent on efficient interaction with its cell surface receptors and vector internalization. Understanding the biology of the host response to adenovirus vectors will impact the design of future generations of these agents aimed at reducing their immunogenicity and improving their safety.