19 August 2016
Scientists at the Medical Research Council Laboratory of Molecular Biology in Cambridge and University College London have uncovered key components of HIV, which they believe could lead to new approaches for drugs to fight the infection according to Hannah Nichols.
HIV infects and kills white blood cells called CD4 lymphocytes (or “T cells”) and can leave the body unable to fight off certain kinds of infections and cancers.
Infections that occur because of HIV are called opportunistic infections because they take advantage of the impaired immune system.
In the United States Agency for International Development (USAID) Gaps report 2016, an estimated 3.5 million people are living with HIV in Nigeria, and over 250,000 people are newly-infected by the virus.
Only certain body fluids – blood, semen, rectal fluids, vaginal fluids, and breast milk – from a person who has HIV can transmit HIV.
Although there is no cure yet for HIV infection, improved treatments allow people living with HIV to slow the virus’ progression and stay relatively healthy for years.
Iris-like pores discovered in HIV
Previously, it was unknown exactly how the virus gets the genetic building blocks it needs to synthesise the DNA to infect the host cell. However, the research team has made new discoveries into this mechanism.
A protein shell known as the capsid surrounds the virus. The researchers found that the capsid contains iris-like pores that open and close like an eye.
The pores can open and close very quickly, enabling them to “suck in” the genetic building blocks called nucleotides that the virus needs to build the DNA to infect the cell, while keeping out any unwanted molecules. This helps to explain why HIV is so successful at evading the immune system.
The discovery, published in the journal, Nature, was made by examining the atomic structure of the capsid and creating mutant HIV viruses, which allowed the team to see the behaviour of the pores.
Dr. Leo James, of the Medical Research Council (MRC) Laboratory of Molecular Biology, says: “We used to think that the capsid came apart as soon as the virus entered a cell, but now realise that the capsid protects the virus from our innate immune system. The channels we’ve discovered explain how the fuel for replication gets into the capsid to allow the viral genome to be made.”
Inhibitor molecule designed to block pores
To prevent the virus from copying itself and infecting more cells, the scientists developed an inhibitor molecule – hexacarboxybenzene – that can block the capsid pores.
The molecule successfully blocks the pores, ensuring that the virus can no longer replicate itself, rendering it non-infectious.
The hexacarboxybenzene molecule is unable to enter human cells, and therefore, cannot help with any cells that have already been infected with HIV.
However, the researchers indicate the findings could lead to both future drugs that could enter human cells and block the pores from within and greater effectiveness of existing treatments, by altering them to penetrate pores.
Additionally, this new prototype molecule could assist in the development of drugs to treat other retroviruses.
This collaborative work between Leo James’s laboratory at the MRC Laboratory of Molecular Biology and Greg Towers at University College London really illustrates the value of taking an interdisciplinary approach to discovery research,” says Dr. Tim Cullingford, Programme Manager for Chemical Biology at the MRC.
“The combination of atomic-level structural work with virology has enabled them to make a finding that will shape the direction of future work in this area,” he added.
Author: Dotun Obatuyi
My name is Dotun Obatuyi (Dotunoba), I hail from Osun state, a public health scientist (monitoring and evaluation specialist), my keen interests are researching, critiquing and writing feature articles on health, science and technology as well as issues around the globe.