If you have ever wondered what HIV looks like when it infects a CD4 T-cell, you will likely find this video fascinating, as it captures the first time HIV transmission has ever been filmed live. The video you are about to watch includes a series of short videos merged into one by LiveScience. The videos were filmed by a team of French researchers who were successful in filming HIV infecting a healthy cell. Before the video could be recorded, the scientists needed to build an experimental model that mimicked genital mucosa being infected by genital fluids that was suitable for live imaging.
The videos demonstrate how once an HIV-infected cell has attached itself to the CD4 T-cell, the HIV-infected cell shoots out a string of viral particles. The virus is then transported through the outer layer of tissue, allowing the inner immune cells to become infected. After a couple of hours, the HIV-infected cell detaches itself from the CD4 T-cell and moves on carrying HIV inside it. The CD4 T-cell becomes destroyed by this process and can no longer function as an immune system defender, which over time, results in the CD4 T-cell count in the body reducing as the viral load increases.
HIV transmission has not been studied much and we had no precise idea of the exact sequence of events leading to HIV infection of genital fluids during sexual intercourse. Neither did we know how immune cells are infected and what the consequences are. The vast majority of new HIV infections are acquired via the genital and rectal mucosa; however, the outer layer, the epithelium, of those tissues varies and affects how HIV enters the body.Morgane Bomsel, Research Team Director at the French National Center for Scientific Research (CNRS)
The researchers reconstructed in vitro human male urethral mucosa based on human cells, the surface of which had been engineered to be red, and an infected white blood cell that was engineered to be fluorescent green and in turn would produce fluorescent green HIV infectious particles. They had to render the system fluorescent to be able to visualise it and track HIV entry in the mucosa by live fluorescent scanning and devise a system to allow the microscope lens to visualise the contact between the cells. UNAIDS Senior Science Adviser, Peter Godfrey-Faussett, called this “a remarkable and beautiful insight into cells associated with viral transmission.”
What really captured the researchers attention was when they recorded the spillage of a string of viruses from the HIV cell, like a “gun showering bullets”, which identified how HIV infects CD4 T-cells. The researchers also found that this “spillage” lasts for a couple of hours, before the cell detaches itself and moves on, looking for another cell to infect as part of the reproduction process. For HIV to survive, the virus needs to continue replicating inside the human body, so this transmission process continues to evolve, which makes the virus stronger, which simultaneously weakens the body’s immune system.
When I was watching this, I immediately thought to myself about how this scientific discovery is so closely aligned to sexual intercourse. The HIV-infected cell is considered to be the donor, so once it enters the body of the HIV-negative person through unprotected sex, it starts looking for a cell to infect, and this cell becomes the target, which is similar to the reproductive process when sperm is searching for an egg to fertilise. Once the HIV-infected cell has found what it’s looking for (the CD4 T-cell), it attaches itself to the cell, then shoots streams of viral particles into the cell, which mimics the sexual act of breeding. Take this sexual comparison a step further and the donor could be considered a gifter and the target could be considered a chaser in terms of bug chasing and gift giving.
Many of the articles you will find about HIV transmission are scientific, so being able to watch this video where the infection process is made very clear really helps you understand on a visual level how this works inside the body. Once HIV infects a CD4 T-cell, it renders the protective qualities of the white blood cell useless by destroying its ability to protect the body. I have also included a graphic that came from the same source to help you more easily understand the HIV infection process, which shows the CD4 T-cell getting infected, before HIV is transferred into the cell, where it then takes control of the cell.
External Websites and Source:
– Live Imaging of HIV-1 Transfer across T Cell Virological Synapse to Epithelial Cells that Promotes Stromal Macrophage Infection – https://www.cell.com/cell-reports/fulltext/S2211-1247(18)30570-9
– LiveScience Video: https://www.youtube.com/watch?v=aPMpD-Zkv6g
Featured Photo: Arek Socha from Pixabay.
Article ID: CC045
Version Control: 1.0 – August 13, 2022: Original article published.