Recombinant viruses are excellent tools for the introduction of genetic material into host cells. There are many choices, and each viral vector has its place. In order to choose the best viral vector for your research goals, ask yourself the following questions:
Do you plan to infect dividing or non-dividing cells?
Do you need transient or stable expression of your gene?
Are you concerned about a possible immune response from your target cell upon infection?
Will you need a higher viral titer, e.g. for in vivo transduction?
Are you worried about transduction efficiency, i.e. how easy it is for the virus to infect your target cell?
Once you understand what you need from your viral expression studies, you’ll want to understand how each viral vector compares to your goals.
Adenovirus can infect a variety of mammalian cell types with high efficiency. They remain epichromosal upon infection (i.e. do not integrate into the host genome), so they are only suitable for transient expression. Adenovirus can be packaged at a relatively high titer. However, infection with adenovirus may result in a high immune response from target cells; it can actually be toxic to certain sensitive cells like primary neurons.
Adeno-Associated Virus (AAV) integrates into the host cell genome at a very specific site in one human chromosome; random insertions are very rare, making it less immunogenic than other viral vectors. Like adenovirus it can infect a variety of mammalian cell types. Overall, AAV can be produced at a moderately high titer and can infect target cells efficiently, but less so than adenovirus.
Retrovirus (e.g. MMLV) can introduce genetic material into the genome of the host cell, making it great for long-term stable expression. MMLV-based retroviruses, however, cannot infect non-dividing cells. Retroviral titer and transduction efficiency is typically lower than that of other viral vectors. Retrovirus infection may lead to a moderate immune response in target cells.
Lentivirus (e.g. HIV-1, FIV, SIV) is a sub-class of retrovirus that can be used for both transient and stable gene expression. Lentivirus can infect both proliferating and non-proliferating cells and generates a low immune response in target cells. Recombinant lentivirus can be produced at a moderately high titer and is efficient in target cell transduction, higher than retrovirus but less than adenovirus.
For more help in selecting the best viral vector, take a look at this comparison chart.