Ever since the human immunodeficiency virus (HIV) was discovered to be the causative organism for acquired immunodeficiency syndrome (AIDS) in 1984, efforts have been underway globally to find a vaccine for the virus.
The HIV has proved a difficult virus to tackle, as it has ways of hiding from the immune system. The virus is reported to directly infect white blood cells (which protect the body against infections) called T-cells. Once the virus enters the T-cells, it evades being attacked by the immune system. Therefore, to be successful, a vaccine must detect the virus before it enters a T-cell.
To accomplish the development of an efficient vaccine, researchers have been concentrating on the viral coat and the proteins on its surface. However, HIV is capable of changing its envelope and hiding certain proteins from being exposed and available for the antibodies to recognize. This characteristic of the retrovirus has made it extremely difficult to design an efficient vaccine.
When HIV comes in contact with T-cells, it first binds to a receptor called CD-4 via a surface protein gp120, undergoes structural transformation and then binds another receptor known as CCR5. When bound to both receptors, the virus enters the T-cell. The best way to attack the virus is when it is transitioning to bind to CCR5. Using this information, Dr. Robert Gallo (a pioneer scientist who discovered that HIV caused AIDS) and his team working at the Institute of Human Virology, USA, have engineered a vaccine that contains a version of gp120.
The vaccine, called the “full-length single chain” vaccine, is aimed to generate antibodies to the virus, which will bind to HIV’s gp120 when it is in the state of transition, just before binding CCR5. This binding should potentially lead to blocking of the virus’s binding to CCR5, thus stopping the infection process.
Dr. Gallo’s team has tested the vaccine in monkeys extensively and thoroughly for the past 15 years. Encouraged by the results, the team has developed the human-grade vaccine, which is to be tested in 60 volunteers in a Phase1 clinical trial. This trial will assess the safety and immune responses in the volunteers.
DoveMed wishes the team well and will continue to bring updates on the vaccine’s progress.
Written by Mangala Sarkar, Ph.D.
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Acquired Immunodeficiency Syndrome (AIDS). (n.d.). Retrieved October 13, 2015, from http://www.dovemed.com/diseases-conditions/acquired-immunodeficiency-syndrome-aids/
HIV Vaccine Research. (n.d.). Retrieved October 13, 2015, from http://www.niaid.nih.gov/topics/hivaids/research/vaccines/Pages/default.aspx