Gene transfer vector

Vectors are the vehicles that are used in gene therapy to transfer the gene(s) of interest [transgene(s)] to the target cells, which will then go on to express the therapeutic protein encoded by the transgene(s). The most important factor in any gene transfer protocol., apart from the gene of interest, is the choice of vector, which can result in either success or failure. Unfortunately, there is no such thing as a ‘good universal vector’; all of the vectors that are currently available have both advantages and disadvantages. For example, one vector might be able to enter target cells very efficiently but once there invokes a strong immune response, resulting in that cell being killed by the immune system. Many factors must be taken into consideration when choosing a vector. The most import ones are: the length of time that the transgene needs to be expressed, the dividing state of the target cells, the type of target cell, the size of the transgene, the potential for an immune response against the vector to be induced, and whether this is deleterious, the ability to administer the vector more than once, the ease of production of the vector, the facilities available, safety issues and regulatory issues. Table 1 (tab001jfo) outlines the advantages, disadvantages and major differences of the gene delivery vectors that are currently in research and clinical use.