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Chapter 5

HLTB21H3 Chapter Notes - Chapter 5: Red Blood Cell, Luc Montagnier, Social Vulnerability

Health Studies
Course Code
Caroline Barakat

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HLTA01 Plagues and People
Chapter 5 A Modern Plague, AIDS
A global disease and the first pandemic of the 21st century
No cure or vaccine
Afflicts 15 million people worldwide
A Look Back
1981 AIDS was first described, 10,000 people worldwide were infected by the virus that causes
AIDS human immunodeficiency virus (HIV)
HIV is a virus where the genetic material in the form of RNA, so in order for it to use the
machinery of the eukaryotic host cell, it must subvert the cell’s machinery to copy viral RNA into
The discovery of HIV began in 1884 with the development of the porcelain filter
Robert Gallo and Luc Montagnier identified the retrovirus responsible for the destruction of
lymphocytes (HIV), where the host immune system was crippled, leading to the clinical
syndrome of AIDS
1948 several compounds that could interrupt the rampant replication of cancer cells
o 1964 - Azidothymidine (AZT) became the first-line treatment for AIDS
HIV’s Target: the Immune System
T lymphocytes the cells that can be infected with HIV
The glycoproteins of the HIV capsid are called gp41 and gp120, which bind and anchor the HIV
to the surface of the cell
CD4 allows for the docking of gp120, after binding there is fusion and entry of HIV
On HIV enters the cell, the capsid breaks down and virus RNA and reverse transcriptase are
released, beginning to synthesize viral DNA from the viral RNA
Following virus assembly, the viruses leave the cell by budding, and in the process the host
lymphocyte is destroyed; released viruses travel via the blood to various lymphoid organs
Because the HIV glycoproteins have a high affinity for CD4, the virus specifically attacks T4
lymphocytes and macrophages
The antibody cannot eliminate the virus because it is unable to act on viruses hidden away
inside the T lymphocyte
The antibody can be useful as a diagnostic test for the presence of HIV (available since 1985).
o If the serum contains antibody to HIV, they are seropositive
o Usually becomes seropositive 6 to 8 weeks after an HIV infection
Approximately 90% infected die within 15 years if untreated
Characteristics of an HIV infection is depletion of T4 cells
Consequences of HIV include:
o Opportunistic infections (PCP, cryptococcal meningitis, toxoplasmosis)
o Severe athlete’s foot
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