HIV has been the focus of intense biological research for quite some time now. HIV, the agent that causes AIDS has successfully eluded our drugs and has been escaping from vaccines as well. Why is this so? What are current hopes and what does future hold in store? Read on to learn more.
HIV & AIDS
HIV or the Human Immunodeficiency Virus was first reported in the 1980s. The HIV agent belongs to the family of retroviruses and causes a condition called AIDS (Acquired Immunodeficiency Syndrome). HIV targets the host immune system thereby rendering the host's body susceptible to any and all invading pathogens. HIV has been reported to have caused fatalities numbering 25 million till date. The disease was originally reported from Africa, although now it is prevalent all over the world.
Causes of HIV & Transmission
HIV targets the immune system, specifically a group of cells known as the (CD4) helper T cells. Once infection has occurred the CD4 cell count starts to decrease and the viral particle load in the blood stream increases steadily. Once sufficient helper T cell counts have been compromised the body can no longer defend itself from invading pathogens and the hosts usually die by any opportunistic infection.
Currently there is no HIV cure. The infection is spread via blood, semen, vaginal fluid and breast milk. Once infected the host can progress into AIDS quickly, though the progress can be slowed with anti-retroviral drugs. If a patient with HIV infection is not treated at the early stages the life expectancy drops considerably.
HIV Cure & Current Hopes
Generally, medicine combats infections and pathogens with antiviral drugs and vaccines, which in the case of HIV are generally ineffective. HIV can mutate quickly and efficiently, making drug targeting extremely difficult. Ideally the drugs against such infections target the pathogen by recognising its physical features, in the case of viral pathogens this would be the protein coat which envelopes the genetic material contained within. The problem with HIV though, is that the protein coat keeps mutating leaving drugs unable to efficiently attack the virus. Vaccines also are ineffective. It is logical to think that with today's molecular biology tools and breakthroughs in genome sequencing and analysis a solution for the menace of HIV should be possible in the near the future.
In fact it is not all bad news. Scientists have made significant progress toward combating HIV. There are certain types of antibodies in the human immune system that have demonstrated an ability to fight HIV. Though, the exact mechanism by which they attack the invading pathogen is not known and we have not yet been able to isolate these selective antibodies until now. A team of scientists from the University of Pennsylvania have been able to identify the gene sequence that codes for these antibodies and have successfully introduced them by gene therapy into infected monkeys. The result was that this gene therapy approach fought off HIV infection effectively.
Yet another significant development is the discovery of the architecture of the HIV-1 RNA genome. Though we already possess the genome sequence of the HIV-1 virus, it has so far not been possible to engineer a way of applying this knowledge to combat the virus. The recent finding of the complete secondary structure of the RNA genome of HIV will allow us to understand in detail about the assembly of the protein components of the protective coat. Since the ways in which proteins fold are controlled by RNA structures formed from the expressed genome, such knowledge allows us to understand how protein coat mutations occur and how they can be combated. The research paper that elucidates the secondary structure and architecture of the RNA genome was published in the journal Nature in June 2009. This finding may very well serve as the missing piece of the puzzle to counter HIV.
- Architecture and secondary structure of an entire HIV-1 RNA genome. Nature 460, 711-716 (6 August 2009) | doi:10.1038/nature08237; Received 11 May 2009; Accepted 22 June 2009