Human Immune Responses to HIV. Human immunodeficiency virus (HIV) is a virus which around 36.9 million people around the globe are currently living with. It is one of the world’s most serious public health challenges and is the cause of Acquired Immune Deficiency Syndrome (AIDS). Hivgov. (2018)

Human Immune Responses to HIV

What is Human immunodeficiency virus (HIV)?

Human immunodeficiency virus (HIV) is a virus which around 36.9 million people around the globe are currently living with. It is one of the world’s most serious public health challenges and is the cause of Acquired Immune Deficiency Syndrome (AIDS). Hivgov. (2018) HIV is part of the retrovirus family which depletes the immune system by eradicating all the immune responses and attacking the immune system which eventually leads to AIDS.

Compans, Richard W. et al. (1989, p.119) Over the past years, the life span of patients with HIV has increased with the aid of many new and more effective antiretroviral drugs and more research being done to extend the life span of infected patients. This short report reviews the effects of HIV on the immune system, how the immune system responds to HIV, the effect of antiretroviral drugs, mental health on the immune system and HIV leading to AIDS.

Figure 1: Generalized retrovirion structure (AIDS and other manifestations of HIV infection)

HIV is a retrovirus which means it only contains one single strand of genetic material, RNA. Ipmglobal. (2019) The way in which it attacks the cells is similar to that of other viruses, but it also has many differences. The HIV cells begin by binding to the receptors present on the surface of the T Lymphocytes. It then dissolves its envelope and merges with the T lymphocyte.

Once inside the T Lymphocyte, the virus releases its contents into the cell and this is when the enzyme reverse transcriptase causes the viral RNA to be copied to the Lymphocytes DNA and produce a viral cell. This cell with then undergo mitosis with the viral DNA causing more infected T lymphocytes. Makadon, Harvey J & Libman, Howard. (2000, p.21)

The immune system responds to a ‘normal’ virus by triggering the second line of defence. The innate immune response begins with the macrophages tracking and locating a host cell via the antigens released which trigger the immune response. The macrophage then engulfs the infected cell and the macrophage undergoes phagocytosis which causes the lysosomes to destroy the cell.  The macrophage will display the antigens on the outer surface, so helper cells can detect them and through antigen antibody complexes, destroy the virus.

Plasma cells then produce the antibodies which bind to the antigens and attack the virus cells and eradicate the virus from the body. The plasma cells will then become memory cells and continuously flow in the blood stream to have a fast secondary response if the pathogen enters the body again. Sompayrac, Lauren (2016, p. 14-16)

This is different to HIV because the virus attaches to and invades the macrophage which renders them useless and causes the primary immune response to become ineffective. The process begins when T lymphocytes originally recognises the antigens on the receptors of the virus cell and move towards it in the attempt to engulf it. The T lymphocyte attempts the method it is used to with an attempt to express the same antigens, so the immune system can produce helper cells and plasma cells.

This fails as the HIV cells binds its envelope with the T lymphocyte and then releases its contents into the T lymphocyte. This causes the macrophage to begin to produce more HIV infected cells and act as a host carrying the virus around the body. Anon (2000, 129–154) Over time, many HIV infected cells spread across the blood stream and the immune system of the infected becomes very weak leading to AIDS. Without any antiretroviral medication, the patient can have a very short life and will eventually die of a minor illness which the immune system could have handled such as thrush or Salmonella. Makadon, Harvey J & Libman, Howard. (2000, p.23)

In the bodies attempt to attack the viral cells, there is a rapid reproduction rate of HIV cells in the blood but then suddenly the amount of HIV cells in the blood lowers which makes it seem like the drugs and immune system have suddenly began to have much greater effect on the HIV. There is also a rise in the detected levels of T helper cells and lymphocytes which adds to the signs of the body successfully attacking the viral cells. This only seems this way temporarily and the constant battle between the cells isn’t over. The immune system is in a losing battle against HIV. Sompayrac, Lauren (2016, p. 224-226)

Antiretroviral drugs can prolong the length of a patient’s life very significantly. There are three main types of antiretroviral drug. From the three, Nucleoside Reverse-Transcriptase Inhibitors; Nonnucleoside Reverse-Transcriptase Inhibitors and Protease Inhibitors, the most effective antiretroviral drug drug is the Protease Inhibitors. These antiretroviral drug drugs have viral suppression of 2 logs or more and work by preventing the HIV from being assembled and released.

Makadon, Harvey J & Libman, Howard. (2000, p.97-106) The virus plants itself in the CD4 lymphocyte and the antiretroviral drug drugs inhibit the breakdown of proteins which inhibits protein synthesis and therefore the production of HIV cells. Manqing Li et al. (2012, p. 128) To prolong the effect of the antiretroviral drugs and to keep the immune system strong for as long as possible, it is crucial for patients living with HIV to prevent any opportunistic infections.

The best way to ensure this is to treat HIV infection aggressively to delay the reduction in immune functions. There are drugs which can raise the CD4 count int the blood and these are effective in controlling the strength of the Immune system and allowing it to be effective in overcoming infections for longer. By increasing the amount of time, the patients’ immune system is working by preventing opportunistic infections, the patient can have a better quality of life for longer and they could also live for longer than the HIV might have allowed them to without these precautions. Makadon, Harvey J & Libman, Howard. (2000, p.130)

The end stages of HIV are when the body’s immune system is very compromised and virtually non-existent. There is a significant decrease in the number of functioning CD4 Lymphocytes which makes the body highly susceptible to opportunistic infections such as pneumonia and tuberculosis (TB). Blattner, W. et al. (1988, p.515) As the immune system depletes, there is a constant decrease in the CD4 count.

Eventually, the immune system will have reached the AIDS stage when the CD4 count is below 500 µl and it is at this point where the immune system can no longer protect the patient from infection. (Volberding et al, 1990) After this point, drugs can be administered to help to increase the CD4 count again but this is only a temporary fix to the issue and the crashing immune system will eventually stop functioning.

The stress and mental health effects of suffering from HIV can also have a highly severe effect on the immune system. Research into the relationship between mental health and HIV has only arisen in recent years and there are significant trends between people living with HIV and mental health troubles such as mood disorders, drug abuse and risk of suicide. ichols, Janice E. (2002 p.133-134)

The immune system suffers from the mental health issues which can be causes by HIV and the way society has become to think of HIV with a negative prejudice. The depletion of the immune system by the HIV cells is accelerated as the immune system is weaker with the stress placed on it from the mental health. If this is eased off the patient, there immune system can be stronger and will be able to attack the HIV virus more effectively without an additional stresses placed on it to weaken it any further. Castés and Hagel. (1999 p.1)

Researches have been trying to produce a vaccine for HIV which would trigger a secondary immune response as the memory cells for HIV would already be in the blood stream. After nearly two decades of failed attempts at this, the focus is now moving onto the innate immune response (also known as the primary immune response) to try to remove the rapid speed of the infection.

By slowing down the viral response, the immune system has more time to be able to vigorously attack the viral cells and to be able to maybe even eradicate HIV from the body without it becoming a life long illness which would eventually lead to AIDS. Jay A. Levy (2001, p.312)

Human Immune Responses to HIV
HIV Report waddendum Main report

HIV was a very stigmatised and negative virus in the past. There were many misconceptions surrounding it which unfortunately, some of these negative judgements have remained with the virus. With antiretroviral drugs, there is a very successful and promising future for both patients with the virus and the future of HIV seems to be quickly propelling in the right direction.

Human Immune Responses to HIV
A structure of HIV

Extensive research and a vast amount of experimentations have brought us so far in the short period of time and with the extended support of the majority, HIV could become a thing of the past with the help of antiretroviral drugs to aid the immune system. Already Levels of HIV in the blood are so low, scientists think the virus is non-transmittable in some cases, so the future looks immense for HIV patients.

The aim of the future research is to make the patients who are currently or will be living with HIV to have unaffected life’s and to be able to forget about the HIV they contracted and be able to continue with life without HIV impacting their life or body’s immune system in anyway.

Bibliography:

  • Hivgov. (2018). Global HIV/AIDS Overview. Available at: https://www.hiv.gov/federal-response/pepfar-global-aids/global-hiv-aids-overview, (Accessed: 22 May 2019).
  • Compans, Richard W. et al. (1989) ‘Cell biology of virus entry, replication, and pathogenesis : proceedings of a Glaxo-UCLA Symposium held at Taos, New Mexico, February 28-March 5, 1988 ’. New York: A.R. Liss. p.
  • Sompayrac, Lauren (2016) How the immune system works . Fifth edition. West Sussex, England: Wiley Blackwell.
  • Jonckheere, H. , Anné, J. and De Clercq, E. (2000), The HIV‐1 Reverse Transcription (RT) Process as Target for RT Inhibitors. Med. Res. Rev., 20: 129-154. doi: 10.1002/(SICI)1098-1128(200003)20:2<129::AID-MED2>3.0.CO;2-A
  • Makadon, Harvey J & Libman, Howard. (2000) HIV . Philadelphia, Pa: American College of Physicians.
  • Manqing Li et al. (2012) Codon-usage-based inhibition of HIV protein synthesis by human schlafen 11. Nature. [Online] 491 (7422), 125–128.
  • Ipmglobalorg. (2019). How HIV Infects a Cell.  Available at: https://www.ipmglobal.org/how-hiv-infects-cell, (Accesed: 24 May 2019)
  • Blattner, W. et al. (1988) HIV Causes AIDS. Science. [Online] 241 (4865), 515–516
  • ichols, Janice E. (2002) Aging with HIV : psychological, social, and health issues . San Diego, Calif., USA: Academic Press.
  • Masafi, Saideh et al. (2018) Effect of Stress, Depression and Type D Personality on Immune System in the Incidence of Coronary Artery Disease. Open access Macedonian journal of medical sciences. [Online] 6 (8), 1533–1544. [online]. Available from: http://search.proquest.com/docview/2097594352/.
  • Castés, M. and Hagel, I. (1999). Immunological Changes Associated with Clinical Improvement of Asthmatic Children Subjected to Psychosocial Intervention. Brain, Behavior, and Immunity, 13(1), pp.1-13.
  • Wormser, Gary P. (2004) AIDS and other manifestations of HIV infection . 4th ed. San Diego, Calif: Elsevier Academic.
  • Volberding, P.A., Lagakos, S.W.1990. Zidovudine in asymptomatic human immunodeficiency virus infection: a controlled trial in persons with fewer than 500 CD4-positive cells per cubic millimeter. New England Journal of Medicine, 322(14), pp.941-949.
  • Jay A. Levy. (2001) The importance of the innate immune system in controlling HIV infection and disease, Trends in Immunology, 22 (6), pp. 312-216

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