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Virsuses: Human Immunodeficiency Syndrome & Acquired Immunodeficiency Syndrome. Outline. Introductory Comments Virus versus bacteria Examples of DNA and RNA containing viruses How RNA containing viruses can replicate Origins of HIV Dr. Hahn and colleagues Characteristics of HIV Particle - PowerPoint PPT Presentation
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Virsuses:Human Immunodeficiency Syndrome
& Acquired Immunodeficiency
Syndrome
Outline• Introductory Comments
– Virus versus bacteria– Examples of DNA and RNA containing viruses– How RNA containing viruses can replicate
• Origins of HIV– Dr. Hahn and colleagues
• Characteristics of HIV Particle– Glycoproteins– Viral genes
• Laboratory Diagnostic Tests– PCR– Western Blot– ELISA
• -------------------------------------------------- Part 2 -------------------------• Treatment• Transmission• Prevention
Bacteria versus Viruses
Note: These STDs are bacterial infections!
• SYPHILIS– Bacterium: Treponema pallidum
• GONORRHEA– Bacterium: Neisseria gonorrhoeae
Viruses
• DNA containing
• RNA containing
DNA containing viruses
• Herpes virus
• Small pox virus
• Hepatitis B
• adenovirus
RNA containing viruses
• Hepatitis A and C• Rabies• Ebola• Measles • Mumps• Polio• HIV
Rabies virus
Measles on the back
HIV
Examples of how RNA viruses replicate
Negative strand
Positive strand
Retro
RETROVIRAL REPLICATION
HUMAN IMMUNODEFICIECY VIRUS
• Family: retrovirus• Genus: lentivirus• Species: HIV 1 and HIV 2• Groups and Subtypes: variety
“Predominant Subtypes of Group M”
• Africa• Americas• China (southeast)• Europe• India• Japan• Thailand
• A;D;C• B• C• B• C• B• E
Dr. Beatrice Hahn & colleagues:Drs. Li and Keele
Greater spot nose monkey Red Cap Mangabey monkey
SIV cpz almost identical to HIV 1
Humans
Pan troglodytes troglodytes
Simian Virus (SIV cpz) almost identical to HIV 1
Sooty mangabey monkey
Simian Virus corresponds to HIV2
HIV: Structure and mechanism of replication
HIV-1 PARTICLE
HIV Glycoproteins
• Lipid Bilayer contains glycoproteins
– Gp 160– Gp 120– Gp 41
T lymphocyte in green and HIV in red
HIV and helper T cells
HIV-1
HOST CELLS: helper T lymphocyte, macrophages
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter24/animation__hiv_replication.html
Budding of HIV from T lymphocyte
HIV
HIV
Mechanism of Infection
VIRAL RNA
PROVIRAL DNA
Infects Th cell
Integrates into host DNA
“activated”LYTIC STAGE storage
LYSOGENIC STAGE
Co-Receptors
CCR5 or CXCR4 (fusin)
Binds naturally occurring chemokines
LYTIC STAGE
The key HIV genes
HIV Diagnostic Tests
• Western Blot
• PCR Directly measures HIV
Polymerase Chain Reaction• Measures proviral DNA within the host DNA
Western BlotIdentifies HIV proteins
Protein ladder
HIV Diagnostic Tests
• ELISA
Indirect evidence of HIV exposure
measures
• A diagnostic test for Antibodies to HIV
Enzyme Linked Immunosorbent Assay
(ELISA)
Antibodies
*Antibodies are proteins produced by our immune system that are
directed against specific antigens.
(Antibody interactions with antigens will also be discussed in our “immungenetics lecture”)
Antibodies Antigens
Immune system Non-self
Now apply these concepts to the diagnostic test known as ELISA to detect antibodies against HIV from a biologic
fluid.
Do any of these individuals carry antibodies to HIV?
ELISA MICROTITER PLATES
Microtiter plate
The ELISA protocol
12
3
4
antigen
sampleLabelled 2nd Ab
Color inducing substrate
Results
POSITIVE ANTI-HIVCOLOR CHANGE
NEGATIVE ANTI-HIVNO COLOR CHANGE
FDA Approves Saliva OraQuick Rapid Test for HIV-1, HIV-2
Antibodies[March 29, 2004]
(similar test is also available for blood samples, see next slides).
OraQuick Rapid Anti-HIV Blood Test
1 2
3 20 minute testCost app. $15.00
Outline• Introductory Comments
– Virus versus bacteria– Examples of DNA and RNA containing viruses– How RNA containing viruses can replicate
• Origins of HIV– Dr. Hahn and colleagues
• Characteristics of HIV Particle– Glycoproteins– Viral genes
• Laboratory Diagnostic Tests– PCR– Western Blot– ELISA
• -------------------------------------------------- Part 2 -------------------------• Treatment• Transmission• Prevention
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