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

RETROVIRAL REPLICATION

HIV

T lymphocyte in green and HIV in red

LYTIC STAGE

Budding of HIV from T lymphocyte

HIV

HIV

Co-Receptors

CCR5 or CXCR4 (fusin)

Binds naturally occurring chemokines

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

HIV Glycoproteins

• Lipid Bilayer contains glycoproteins

– Gp 160– Gp 120– Gp 41

HIV: Structure and mechanism of replication

HIV-1 PARTICLE

Dr. Beatrice Hahn & colleagues:

Drs. Li and Keelehttp://www.ucsf.edu/news/2009/12/8212/beatrice-hahn-discusses-gombe-national-park-chimp-research-and-origin-ai

“Predominant Subtypes of Group M”

• Africa• Americas• China (southeast)• Europe• India• Japan• Thailand

• A;D;C• B• C• B• C• B• E

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

Mechanism of Infection

VIRAL RNA

PROVIRAL DNA

Infects Th cell

Integrates into host DNA

“activated”LYTIC STAGE storage

LYSOGENIC STAGE

The key HIV genes

ELISA LAB

• We will now move to the ELISA lab but will return to review the principles of the ELISA as well as other HIV based clinical tests.

HIV Diagnostic Tests

• Western Blot

• PCRDirectly measures HIV

Polymerase Chain Reaction• Measures proviral DNA within the host DNA

Western BlotIdentifies HIV proteins

Protein ladder

HIV Diagnostic Tests

• ELISA• (we have discussed

this in lab)

Indirect evidence of HIV exposure

• 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

1

23

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