HIV Flashcards
LO
- To know about the history, incidence and clinical progression of AIDS.
- To understand the biology of the AIDS virus and how it causes immunosuppression.
- To learn about the immune response to the AIDS virus
- Be aware of forms of chemotherapy and issues of vaccine development in AIDS.
Key topics
- History of AIDS (Acquired Immunodeficiency Syndrome)
- The human immunodeficiency virus (HIV)
- Structure
- Replication cycle
- Clinical course of HIV infection
- Immunology of HIV infection
Effects of HIV on the immune system
Immune response to HIV
- Chemotherapy of AIDS
- HIV vaccines and microbiocides
The story of AIDS began in 1981, when a cluster of unusual disease were observed in certain groups of people. What were the two main diseases and what were they caused by?
- pneumonia caused by a yeast, Pneumocystis carinii
- and an unusual tumour called Kaposi’s sarcoma caused by human herpes virus 8
Initially AIDS was noticed in homosexual men before later symptoms appearing in who? What did this suggest about the nature of the virus?
- Initially in homosexual men but later the same symptoms appeared in intravenous drug users and haemophiliacs who were injecting blood-clotting factors.
- This pattern of disease occurrence suggested that a transmittable agent was responsible for the diseases
What was an unusual aspect noticed about AIDS during its discovery?
. Unusual aspect of these diseases was they were only seen in immunosuppressed people and not in people with a fully functioning immune system.
What were some observations made about the individuals who had the disease?
The observation that individuals with these diseases had low numbers of CD4 T cells was consistent with immunosuppression
When was the term for the diseases used by the CDC?
1982 the term acquired immunodeficiency syndrome, or AIDS, was used by the Centres for Disease Control (CDC) in Atlanta to describe the disease
In 1983, shortly after AIDS discovery, what was discovered?
1983 virus causing isolated from lymph node of an infected individual by Luc Montagnier’s group in Paris and was called the human immunodeficiency virus, or HIV for short.
What was identified in 1986?
Second strain of HIV was identified in 1986; called HIV-2 and first strain was renamed HIV-1
Tell me how HIV-1 and HIV-2 differ?
HIV-1 and HIV-2 differ in their virulence (severity and how harmful it is) and geographical location.
HIV-2 is less virulent than HIV-1 and is found primarily in western Africa.
What have genetic studies shown about HIV-1 and HIV-2?
Tell me the origins of both HIV-1 and HIV-2
Genetic studies showed that both HIV-1 and HIV-2 are natural viruses of primates that have jumped species to infect humans.
HIV-1 came from chimpanzees
and HIV-2 from the sooty mangabey.
How did we as humans get HIV from animals?
Both animals are killed for food and assumed that it was during this process that the virus initially infected humans.
Tell me an effect we as humans had from HIV that the animals didnt?
HIV-1 and HIV-2 do not cause immunosuppression in chimpanzees or sooty mangabeys; only when virus crossed into humans did it cause the profound immunosuppression seen in AIDS.
Estimated since 1981, how many worldwide have been infected, and died?
Estimated since 1981 over 75 million people worldwide were infected with HIV and over 32 million died (43% dead); 2 million died in 2007 and 2008.
Where is the highest rate of increase in HIV infection seen?
How has this expected life-expectancy in this area?
The highest rate of increase in HIV infection is seen in sub-Saharan Africa; estimated 20-40% of young adults are infected.
Thus, life expectancy in sub-Saharan Africa almost halved; it is now in the 30s-40s instead of approaching 70, the estimated life expectancy if AIDS pandemic had not occurred.
What is the pattern of spread of HIV in Africa? Compare this to that seen in more developed countries?
- Pattern of spread in Africa appears to be primarily by heterosexual contact and has a similar incidence in men and women.
- By contrast, spread in Europe, the USA and Oceania are still mostly among ‘high-risk’ groups such as homosexuals and intravenous drug users, much more prevalent in men than women.
- However, signs in USA that pattern of spread is changing, with more women being infected.
- End of 2008, women accounted for 50% of all adults living with HIV worldwide
Sub-sahara stats

Women can pass HIV onto their children, how do they do this?
Women can pass on HIV to their children via childbearing and breastfeeding
What are the two 1 strains of HIV?
The two 1 strains of HIV are called HIV-1 and HIV-2.
Also, many different subtypes of HIV-,1 so vaccines needed to protect against all subtypes.
Why are there different varients of HIV and why is this important?
- Also, HIV has very high mutation rate, giving rise to different forms of the virus known as variants.
- Variants important because, as described later, they differ in which cell types they can infect.
- Although different strains, subtypes and variants of HIV, very similar in structure and replication; therefore, will be described together and referred to collectively as HIV.
What type of virus is HIV? What does this mean?
- HIV retrovirus (lentivirus family)
- contains RNA as genetic material
- Retrovirus: any of a group of RNA viruses which insert a DNA copy of their genome into the host cell in order to replicate, e.g., HIV.
What does the HIV genome contains and what is this bound by?
HIV genome contains…
- 2 molecules of single-stranded RNA;
- each bound by a molecule of reverse transcriptase
- Within genome are also a p10 protease and a p32 integrase
What is the HIV genome surrounded by?
Genome is surrounded by nucleocapsid consisting of inner layer of protein p24 and outer layer of protein p17
(both part of Gag (group specific antigen) polyprotein complex)
What does the outer portion of the virus consist of?
Lipid envelope derived from host cell membrane























