Use in gene therapy and vaccination
Adenoviruses have long been a popular viral vector for gene therapy due to their ability to affect both replicating and non-replicating cells, accommodate large transgenes, and code for proteins without integrating into the host cell genome. More specifically, they are used as a vehicle to administer targeted therapy, in the form of recombinant DNA or protein. This therapy has been found especially useful in treating monogenic disease (e.g. cystic fibrosis, X-linked SCID, alpha1-antitrypsin deficiency) and cancer. In China, oncolytic adenovirus is an approved cancer treatment. Specific modifications on fibre proteins are used to target Adenovirus to certain cell types; a major effort is made to limit hepatotoxicity and prevent multiple organ failure. Adenovirus dodecahedron can qualify as a potent delivery platform for foreign antigens to human myeloid dendritic cells (MDC), and that it is efficiently presented by MDC to M1-specific CD8+ T lymphocytes.
Adenovirus have been used to produce viral vector COVID-19 vaccines. "In four candidate COVID-19 vaccines... Ad5... serves as the 'vector' to [transport] the surface protein gene of SARS-CoV-2". The goal is to genetically express the spike glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A replication-deficient chimpanzee adenovirus vaccine vector (ChAdOx1) is used by the Oxford–AstraZeneca COVID-19 vaccine that has been approved for use. The Johnson & Johnson COVID-19 vaccine uses modified recombinant adenovirus type-26 (Ad26). Recombinant adenovirus type-5 (Ad5) are being used by Ad5-nCoV, ImmunityBio and UQ-CSL V451. The Gam-COVID-Vac (aka Sputnik-V) product is innovative because an Ad26 based vaccine is used on the first day and an Ad5 vaccine is used on day 21. Another one is ChAd-SARS-CoV-2-S; the vaccine reportedly prevented mice that were genetically modified to have human ACE2 (hACE2) receptors, presumably receptors that allow virus-entry into the cells, from being infected with SARS-CoV-2.
Possible issues with using Adenovirus as vaccine vectors include: the human body develops immunity to the vector itself, making subsequent booster shots difficult or impossible. In some cases, people have pre-existing immunity to Adenoviruses, making vector delivery ineffective.
The patient is in good condition, with an expected hospital discharge in the next few days, a spokeswoman said
A panel of advisers to the Centers for Disease Control and Prevention voted earlier Friday to recommend resuming use of the Johnson & Johnson vaccine. The shots are expected to be accompanied by a new warning about an increased risk of rare but serious blood clots for adult women under 50.
Time to revise the warning--already. Again: This adenovirus shot is experimental. Nobody knows what all could happen in the short run, much less in the long run.