The Persistent Crisis of Human Immunodeficiency Virus
Posted on 2024-12-02
Overview
Human Immunodeficiency Virus (HIV) belongs to the virus family Retroviridae, classified within the Lentivirus genus (1). First isolated and identified in 1983, HIV originated from several zoonotic transmission events from non-human primate simian immunodeficiency viruses (SIV) in Central African chimpanzees and West African sooty mangabey monkeys (2). Since its discovery, the HIV epidemic has caused an estimated 42.3 million deaths, with 39.9 million people living with HIV worldwide in 2023 (3).
Pathogenesis
HIV primarily targets T helper cells, key regulators of humoral and cellular immune responses. A viral tropism that leads to an extreme form of immune subversion, resulting in a continuous loss of CD4+ T helper cells, and a weakened immune system (4). As the disease progresses, known as acquired immunodeficiency syndrome (AIDS), the ability to prevent infections from other pathogens collapses and death may occur by opportunistic infections (5).
Types of HIV
There are two types of HIV, HIV-1 and HIV-2, HIV-1 is responsible for over 90% of HIV infections worldwide, whereas, HIV-2 is currently mainly present in West Africa. The main difference between the two infections is the progression to immunodeficiency occurs more slowly in HIV-2 infection compared to HIV-1 (6). As HIV-1 has a greater infectivity, it is also more readily transmitted. In terms of origin, HIV-1 and HIV-2 are considered to have been derived from separate simian to human transmissions (7). Abbexa has a product range that supports the research into the HIV serotypes:
Transmission and Detection
HIV transmission occurs most frequently during sexual contact through exposure to infectious virions penetrating mucosal surfaces (8). HIV detection is possible at the earliest 10 days post-infection, employing sensitive polymerase chain reaction (PCR) tests. However, in scientific research, antigen testing is the method most commonly used to diagnose HIV infections (9). Abbexa offers a range of products for HIV detection:
Treatment and Prevention
To date, antiretroviral treatment (ART) is the only available treatment for HIV infections in humans, relying on the combination of three to four viral replication inhibitors. However, ART does not cure the infection, it merely limits the progression of AIDS, transforming HIV from a fatal to a chronic disease (10). Efforts to develop an HIV vaccine have been ongoing since the early 1980s but remain unsuccessful, due to the high mutation and recombination rates of HIV (11).
Several HIV vaccines are currently in clinical trials. Within these, VIR-1388, currently in Phase I (NCT05854381), is evaluating the safety and ability to induce HIV-specific immune response in people. In particular, this vaccine is based on the human cytomegalovirus vector platform and is designed to stimulate the body to produce T cells that recognise several HIV proteins (12).
References
1. The chronology of AIDS research. Nature. 1987;326(6112):435–6.
2. Sharp PM, Hahn BH. Origins of HIV and the AIDS Pandemic. Cold Spring Harb Perspect Med [Internet]. 2011 Sep [cited 2024 Nov 29];1(1):a006841. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC3234451/
3. HIV [Internet]. [cited 2024 Nov 29]. Available from: https://www.who.int/data/gho/data/themes/hiv-aids
4. van Heuvel Y, Schatz S, Rosengarten JF, Stitz J. Infectious RNA: Human Immunodeficiency Virus (HIV) Biology, Therapeutic Intervention, and the Quest for a Vaccine. Toxins (Basel) [Internet]. 2022 Feb 1 [cited 2024 Nov 29];14(2):138. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC8876946/
5. Djawe K, Buchacz K, Hsu L, Chen MJ, Selik RM, Rose C, et al. Mortality Risk After AIDS-Defining Opportunistic Illness Among HIV-Infected Persons—San Francisco, 1981–2012. J Infect Dis [Internet]. 2015 Nov 1 [cited 2024 Nov 29];212(9):1366–75. Available from: https://dx.doi.org/10.1093/infdis/jiv235
6. Nyamweya S, Hegedus A, Jaye A, Rowland-Jones S, Flanagan KL, Macallan DC. Comparing HIV-1 and HIV-2 infection: Lessons for viral immunopathogenesis. Rev Med Virol [Internet]. 2013 Jul 1 [cited 2024 Nov 29];23(4):221–40. Available from: https://onlinelibrary.wiley.com/doi/full/10.1002/rmv.1739
7. Moore BA, Barnett JE. The Origin, Evolution, and Epidemiology of HIV-1 and HIV-2. Case Studies in Clinical Psychological Science: Bridging the Gap from Science to Practice [Internet]. 2017 [cited 2024 Nov 29];(August):1–7. Available from: https://academic.oup.com/book/24776/chapter/188354060
8. Shaw GM, Hunter E. HIV Transmission. Cold Spring Harb Perspect Med [Internet]. 2012 Nov 1 [cited 2024 Nov 29];2(11):a006965. Available from: http://perspectivesinmedicine.cshlp.org/content/2/11/a006965.full
9. Deeks SG, Overbaugh J, Phillips A, Buchbinder S. HIV infection. Nature Reviews Disease Primers 2015 1:1 [Internet]. 2015 Oct 1 [cited 2024 Nov 29];1(1):1–22. Available from: https://www.nature.com/articles/nrdp201535
10. Carr A, Mackie NE, Paredes R, Ruxrungtham K. HIV drug resistance in the era of contemporary antiretroviral therapy: A clinical perspective. Antivir Ther [Internet]. 2023 Oct 1 [cited 2024 Nov 29];28(5). Available from: https://journals.sagepub.com/doi/10.1177/13596535231201162
11. Lee JH, Crotty S. HIV vaccinology: 2021 update. Semin Immunol. 2021 Jan 1;51:101470.
12. Clinical Trial of HIV Vaccine Begins in United States and South Africa | NIAID: National Institute of Allergy and Infectious Diseases [Internet]. [cited 2024 Nov 29]. Available from: https://www.niaid.nih.gov/news-events/clinical-trial-hiv-vaccine-begins-united-states-and-south-africa