Can genes transduced by adeno-associated virus vectors elicit or evade an immune response?

Vectors derived from the adeno-associated viruses (AAV) have been successfully used for the long-term expression of therapeutic genes in animal models and in patients. Stable expression of the transgene in the transduced cells can be used to correct disease stemming from genetic deficiencies. One of the major advantages of these vectors is reported to be the absence of deleterious immune responses following gene transfer. However, recent studies have shown that AAV vectors elicit humoral and cellular responses against the transgene products. This review article will focus on these two unique yet converse aspects of AAV: the ability to elicit host immune response to destroy target cells containing the transduced protein and the ability to evade immune response leading to stable expression of the transduced genes.