An Exploration into the Science Behind HIV Infections

Theme: Health Issues and Disease

Carlotta Ceccarelli

Perhaps a few of us can say they have heard about the stories of stars like Freddie Mercury, Rock Hudson or Anthony Perkins. Unfortunately, they all have one thing in common, which is their passing from AIDS, a late and deadly stage caused by the infection of HIV [1]. The purpose of my article today is to share the research I conducted on the biochemistry behind the public health crisis of many countries around the world. Due to insufficient funding for health programmes and the societal obstacles caused by endless stigmatization, today 37.9 million people are living with HIV since the start of its epidemic [2]. In light of Pride Month, our team is here to recognise how HIV disproportionately affects the LGBTQ community and how the prejudice towards these groups continue to make everyone particularly unprotected from infection.

The HIV enters our bodily systems via the bloodstream, this transmission could be made in various ways such as but not subject to our blood, semen, vaginal fluids or breastmilk. The virus attacks a myriad of cell types, but particularly the cell known as the T cell. The more technical term for it is a T-lymphocyte, they are produced in our bone marrow and are an essential part of our lymphatic system [3]. They are a type of white blood cell, where they use an ‘identification tag system’ to bind with viral antigens, releasing perforins and cytotoxins to destroy the virus in the cell. In simple words, they latch onto unknown cells that enter our bodies, in hopes of eventually destroying them to prevent any harm they may bring with them. Now how would HIV be able to attack our white blood cells? This is because HIV is not seen as foreign, the ‘spikes’ evident surrounding the envelope of the virus are called glycoproteins- these are used as a disguise from the white blood cells. The mixture of gp14 and gp120 glycoproteins allow HIV to attach on to the white blood cell receptors. They feed off of killing white blood cells to thrive, they can’t replicate on their own otherwise! [4]. What I also found interesting amid this pandemic is that the novel Covid-19 virus invades in a very similar manner, hence why the immunocompromised are at a significantly higher risk [5].

Electron Micrograph image of the HIV assembling on a T-lymphocyte [6]

Although the primary victims are T-lymphocytes, HIV can attack any cell with a CD4 receptor on its surface. This, therefore, may include other vital cells to our immunity such as dendritic cells, macrophages and monocytes. The virus can essentially hack into their systems, injecting enzymes as well as RNA strands which facilitate replication. The HIV cell becomes integrated, it does this by converting the RNA strands injected into DNA, hijacking the T-lymphocyte host cell DNA with this newly formulated one utilizing integrase enzymes [7]. This cycle is vicious, copies of the virus are made which then go onto attacking even more T-lymphocytes and so forth. The issue lies in the fact that HIV is classed as a lentivirus, where the time between exposure of the virus and its first symptoms are excruciatingly long, with some even being asymptomatic for up to 10 years. During this time, the infected person is becoming gradually weaker, where the supply of CD4 receptor cells is decreasing [8]. This could also mean that the infected individual is completely unaware of their own danger, potentially spreading disease to people around them unknowingly. Once you reach a value below 200 cells/mm^3 of CD4 receptor cells, you are diagnosed with AIDS. This is the point where the immune system is so frail that it becomes much easier to die from diseases such as cancer or pneumonia, as a result of the body not being able to defend for itself.

Hopefully being given an introduction to the science behind HIV infections, we can realise and raise awareness about this disease not being subject to particular groups due to outdated beliefs. We must become advocates for early detection of this dreadful disease, there are far too many people today who remain silenced out of fear [9]. There are countless centres for testing, methods for safe sexual fluid barriers, means to find clean needles and pharmaceuticals to prevent the development into AIDS. Responsible use of these resources should not go underutilized due to someone’s sexual preference or gender orientation. If you are curious about more HIV topics I encourage you to hop on this link: https://www.cdc.gov/stophivtogether/

Glossary:

• AIDS- AIDS (Acquired Immunodeficiency Syndrome), A disease of the immune system due to infection with HIV.

• HIV- HIV (human immunodeficiency virus) is a virus that attacks cells that help the body fight infection, making a person more vulnerable to other infections and diseases.

• LGBTQ- An initialism that stands for lesbian, gay, bisexual, transgender and queer.

• T-lymphocyte- A lymphocyte of a type produced or processed by the thymus gland and actively participating in the immune response.

• Lymphatic system- The network of vessels through which lymph drains from the tissues into the blood.

• Perforins- A protein, released by killer cells of the immune system, which destroys targeted cells by creating lesions like pores in their membranes.

• Cytotoxins- Cytotoxicity is the quality of being toxic to cells.

• Glycoproteins- Any of a class of proteins which have carbohydrate groups attached to the polypeptide chain.

• Immunocompromised- Having a weakened immune system. People who are immunocompromised have a reduced ability to fight infections and other diseases.

• CD4- A glycoprotein found on the surface of immune cells such as T helper cells, monocytes, macrophages, and dendritic cells.

• Dendritic cells- A type of antigen-presenting cell found in many tissues throughout the body.

• Macrophages- A large phagocytic cell found in stationary form in the tissues or as a mobile white blood cell, especially at sites of infection.

• Monocytes- A large phagocytic white blood cell with a simple oval nucleus and clear, greyish cytoplasm.

• Enzymes- A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.

• RNA- Ribonucleic acid, a nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins, although in some viruses RNA rather than DNA carries the genetic information.

• Integrase enzymes- An enzyme produced by a retrovirus that integrates.

• Lentivirus- Any of a group of retroviruses producing illnesses characterized by a delay in the onset of symptoms after infection.

• Asymptomatic- Producing or showing no symptoms.

References:

1. HIV.gov. 2020. What Are HIV And AIDS?. [online] Available at: <https://www.hiv.gov/hiv-basics/overview/about-hiv-and-aids/what-are-hiv-and-aids> [Accessed 11 June 2020].

2. KFF. 2019. The Global HIV/AIDS Epidemic. [online] Available at: <https://www.kff.org/global-health-policy/fact-sheet/the-global-hivaids-epidemic/#:~:text=Approximately%2075%20million%20people%20have,the%20beginning%20of%20the%20epidemic.> [Accessed 11 June 2020].

3. Encyclopaedia Britannica. 2020. T Cell CYTOLOGY. [online] Available at: <https://www.britannica.com/science/T-cell> [Accessed 11 June 2020].

4. Avert. 2019. THE SCIENCE OF HIV AND AIDS - OVERVIEW. [online] Available at: <https://www.avert.org/professionals/hiv-science/overview> [Accessed 11 June 2020].

5. Betsaida, A., 2020. Novel Coronavirus Attacks And Destroys T Cells, Just Like HIV. [online] News Medical Life Sciences. Available at: <https://www.news-medical.net/news/20200413/Novel-coronavirus-attacks-and-destroys-T-cells-just-like-HIV.aspx> [Accessed 12 June 2020].

6. Roehr, B., 2019. Scientists Identify Factors That Make People Naturally Resistant To H.I.V.. [online] SMITHSONIANMAG.COM. Available at: <https://www.smithsonianmag.com/science-nature/scientists-identify-factors-make-people-naturally-resistant-hiv-180972092/> [Accessed 12 June 2020].

7. YouTube.com. 2020. The Science Of HIV/AIDS. [online] Available at: <https://www.youtube.com/watch?v=FDVNdn0CvKI&frags=pl%2Cwn> [Accessed 12 June 2020].

8. Meštrović, T., 2018. What Is Lentivirus?. [online] News Medical Life Sciences. Available at: <https://www.news-medical.net/life-sciences/What-is-Lentivirus.aspx> [Accessed 12 June 2020].

9. Human Rights Campaign. 2017. How HIV Impacts LGBTQ People. [online] Available at: <https://www.hrc.org/resources/hrc-issue-brief-hiv-aids-and-the-lgbt-community> [Accessed 12 June 2020].