Download HIV 5

IMMUNODEFICIENCIES
HIV
324 PHT
Dr. Sarah I. Bukhari
PhD in Clinical Microbiology
Department of Pharmaceutics
Office: 06 - 3rd floor
[email protected]
Objective:
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Describe immunodeficiency

Types of immunodeficiency diseases
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HIV
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Origin and history
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Structure
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Pathogeneicity
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Stages of HIV infection
Immunodeficiency
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The absence of a sufficient immune response, which can be either:
Congenital
Acquired
Congenital Immunodeficiencies
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Defect or absence in a number of inherited genes
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DiGeorge’s syndrome
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An animal equivalent; is the Nude hairless mouse
Acquired Immunodeficiencies
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A Varity of drugs, cancers or infectious agents

Hodgkin's disease: (a type of cancer) lowers the
cell-mediated response.
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Removal of spleen : decreases humoral immunity.
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Many viruses including HIV
HIV
Origin & history
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1981: In US, cluster of Pneumocystis pneumonia and Kaposi's
sarcoma in young homosexual men discovered. The men showed
loss of immune function.
1983: Discovery of virus causing loss of immune function and was
called the human immunodeficiency virus or HIV.
1986: A second strain of HIV was identified and was called HIV-2
and the first strain was renamed HIV-1
HIV-1 and HIV-2 differ in their virulence and geographical location
Origin & history
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Genetic studies indicated that the HIV-2 is a mutation of a simian
immunodeficiency virus (SIV) where mangabey monkeys in West
Africa are naturally and harmlessly infected with this SIV
More recently, studies show that HIV- l (the primary HIV found
worldwide in humans) is genetically related to another SIV that is
carried by chimpanzees in Central Africa
HIV is thought to have crossed the species barrier into humans in
central Africa in the 1930 
Origin & history

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Patient who died in 1959 in Congo is the oldest known case.
Virus spread in Africa as result of urbanization. World-wide
spread through modern transportation and unsafe sex.
Norwegian sailor who died in 1976 is the first known case in
Western world.
The human immunodeficiency virus (HIV)

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HIV is not synonymous
with AIDS
The structure of HIV
HIV, of the genus lentivirus,
is a retrovirus
Clades (Subtypes) of HIV
Infectiveness & Pathogenicity of HIV
1. Attachment
2. Fusion
3. Entry
Figure 19.13
** T-cells, Macrophages and monocytes
HIV is often spread by dendritic cells, which pick up the virus and carry it to the lymphoid
organs. There it contacts cells of the immune system, most notably activated T cells, and
stimulates an initial strong immune response.
Latent vs. Active HIV Infection in CD4+ T
Cells
Latent
Active
Latent vs. Active HIV Infection in Macrophages
Activated macrophages
Latently infected
macrophages
Evasion of immune system

Subset of HIV infected cells, become long lived memory cells
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Cell-cell fusion
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Rapid antigenic changes
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Retroviruses have high mutation rate compared with DNA
viruses
lack the corrective “proofreading” capacity of DNA viruses.
These dramatic numbers illustrate the potential problems of
drug resistance and obstacles to the development of vaccines
and diagnostic tests.
The stages of HIV infection
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Phase 1: Asymptomatic or chronic lymphadenopathy
Phase 2: Symptomatic; early indications of immune failure
such as infections by Candida albicans, which can appear in
the mouth, throat, or vagina. Other conditions may include
fever and persistent diarrhea.
Phase 3 is AIDS: Characterized by indicator conditions, such
as: CMV, TB, Pneumocystis, toxoplasmosis, and Kaposi's
sarcoma
The Progression of HIV Infection
Thank you
1st December