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 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 hill.com/sites/ /student_view0/chapter24/animat ion__hiv_replication.html

Budding of HIV from T lymphocyte HIV

Mechanism of Infection VIRAL RNA PROVIRAL DNA Infects T h 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 Blot Identifies 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 antigen sample Labelled 2 nd Ab 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).

OraQuick Rapid Anti-HIV Blood Test minute test Cost 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 Treatment Transmission Prevention