Question

what virus can i use to treat pituitary microadenoma and how? what is the process? please explain in full details.

Answer 1

Retroviruses, such as MMLV, and lentiviruses, such as HIV, are integrating viruses. The nonintegrating viruses include adenoviruses, herpesvirus and the adeno-associated viruses (AAV) can be used to treat pituitary microadenoma . AAV are sometimes able to integrate but usually do not

Retroviruses and lentiviruses are RNA viruses which are considered advantageous because they are integrating viruses. The ability to incorporate their DNA into the host allows for the therapeutic gene to be perpetually present in the genome of the cells infected and can be passed on to future generations of that cell. Lentiviruses have an even better advantage due to their ability to transduce dividing and nondividing cells This unique characteristic makes them strong candidates for gene therapy. Unfortunately there are disadvantages that go along with these integrating vectors. The possibility of insertional mutagenesis is a big concern or integration within an oncogene which could therefore lead to cancer With lentiviruses, the fear that recombination could lead to HIV in gene therapy patients is a drawback, even though the vectors have been constructed in such a way that recombining is a miniscule possibility.

As for the non-integrating viral vectors, the adenovirus is a good candidate for gene therapy. This double stranded DNA virus infects cells and its genome enters the nucleus of the cell and remains episomal The adenoviruses have been made replication defective by deleting the E1 and E3 regions, therefore not only decreasing the possibility of recombinants but also adding the ability to host a larger transgene. Unfortunately, the disadvantage for adenoviruses is that most people have been pre-exposed to an adenovirus and therefore have immunity to the viral proteins. This anti-adenoviral immunity can reduce transgene expression , leading to an ineffective therapy. In order to avoid the adverse immune-mediated side effects due to pre-existing immunity, high-capacity, gutless adenoviral vectors have been developed .These vectors do not encode, and therefore do not express most of the viral proteins and therefore are much less immunogenic than the first generation . Of course, this vector, too, has its limitations. The primary disadvantages with the gutless vector are the difficulty involved in producing large quantities and the possibility of helper virus contamination.

Another commonly used viral vector is the adenoassociated virus (AAV) which is a single stranded DNA virus. The AAV vectors are considered non-integrating vectors although they can sometimes integrate into the host genome within active genes .The initial AAV vectors were produced simply by replacing viral genes with the transgene cassette. With recombination being a strong possibility with AAV, future AAV vectors were developed to prevent wild-type AAV from occurring . The downside to AAV vectors is the small packaging capacity (~4–5kb). This has been improved due to the fact that these vectors concatamerize after transduction .therefore giving one the ability to put half of a transgene in one vector and half of the transgene in another vector which will end up as a reconstituted functional transgene.