Immunology wars: The battle with HIV

Immunology wars: The battle with HIV

When a virus winds up inside the body, it’s usually
met with a furious onslaught from the immune system. White blood cells immediately
respond by releasing antiviral proteins, attacking infected cells and recruiting backup. Usually this is enough, but there’s one virus that
pushes the immune system beyond its limits – HIV. HIV infects one of the immune cells that is central to
the body’s response to pathogens – the helper T cell. First, the virus attaches and enters. Once inside, the virus moves towards the nucleus,
along with its enzymes and genetic material. One of these enzymes – reverse transcriptase – converts the viral RNA into a length of DNA, which inserts into the cell’s genome,
forcing the cell to spew out HIV proteins and genetic material to make new copies of the virus. These new viruses escape the cell to infect others. HIV levels rise rapidly in the body, but the immune system doesn’t go down without a fight. Inside infected cells, antiviral proteins called restriction
factors work to shut down virus production whilst others stop the virus from escaping the cell. Outside, white blood cells, called
B cells, produce neutralising antibodies, which bind to surface spikes on HIV particles
and stop them entering healthy helper T cells. The greatest assault comes from killer T cells and natural killer cells which seek and destroy infected cells directly. They release a protein called perforin,
which punctures the infected cells, allowing enzymes to be injected,
triggering auto-destruction. For a while, the defence holds and virus levels
drop, but HIV begins its counter attack. It disables the cell’s antiviral proteins, allowing
new virus particles to leave the cell. It also constantly mutates
inside the cell to evade detection – the immune system can’t fight what it can’t see. Eventually, the immune
system wears itself out. Killer T cells activated for too long become
exhausted and no longer respond to infection. Also, the body loses the ability to make new helper T cells to replace those killed in the fight and
as a result, their numbers plummet. Ultimately, the body becomes immunodeficient,
and this condition is known as AIDS. Without treatment, exposure to otherwise
harmless microbes can be fatal. We still have no way of eliminating
HIV from the body completely. There is no cure, and hidden reservoirs
of HIV will rebound if treatment stops. But treatment with antiretroviral drugs can swing
the balance, allowing the immune system to recover from battle and live to fight another day.

27 Replies to “Immunology wars: The battle with HIV”

  1. The new episode of Cells at Work looks great!… minus all the death.
    (seriously though, nice video)

  2. I would be very grateful if a sience channel could cite to some research paper. For the last part, I'm not sure there is clear evidence supporting this.

  3. I wonder if Magic Johnson would have caught HIV sooner, we would already be even further in this battle… almost 30 years have passed since then. Before 1991 it was 'their' disease, after it became a public health threat.

  4. i alway wonder why we never see big budget movies in hollywood that are inspired by body systems and phenomenon! a movie about the immune system battles would be better than a Marvel intergalactic wars movie!
    just an opinion

  5. Yeah, this project gives a huge amount of profits to the pharmaceutical industry. =D We are just like cattle in their hands.

  6. Excellent video, really informative and the animation is engaging and compliments the science really well! Top work guys 👍🏻

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