Virsuses: Human Immunodeficiency Syndrome & Acquired Immunodeficiency Syndrome

Outline Introductory Comments Origins of HIV 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

Co-Receptors Binds naturally occurring chemokines CCR5 or CXCR4 (fusin)

HIV and helper T cells 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

HIV: Structure and mechanism of replication

HIV-1 PARTICLE

Dr. Beatrice Hahn & colleagues: Drs. Li and Keele http://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 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 Infects Th cell VIRAL RNA Integrates into host DNA “activated” PROVIRAL DNA 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 PCR Directly measures HIV

Polymerase Chain Reaction Measures proviral DNA within the host DNA

Western Blot Identifies HIV proteins Protein ladder

(we have discussed this in lab) Indirect evidence of HIV exposure HIV Diagnostic Tests ELISA (we have discussed this in lab) Indirect evidence of HIV exposure

Enzyme Linked Immunosorbent Assay (ELISA) A diagnostic test for Antibodies to HIV 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

The ELISA protocol sample Labelled 2nd Ab antigen 3 2 1 4 Color inducing substrate

Results POSITIVE ANTI-HIV COLOR CHANGE NEGATIVE ANTI-HIV NO 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).

1 2 OraQuick Rapid Anti-HIV Blood Test 20 minute test Cost app. $15.00 3