HIV and AIDS

Immune System Overview

HIV lives in these cells

Review how viruses replicate and are transmitted

HIV

life

cyc

le

Typical progress of HIV infection

Importance of HIV as case study

1. Diversity of viruses and viral types:

Importance of HIV as case study

2. Metabolism and genetics:

• provirus stage lives inside cell, integrated with cell’s genome

• virion is particle that moves from cell to cell. In case of HIV, lives in blood and other body fluids:

– blood: 1000-100,000 virions per ml – Semen: 10-50 virions per ml– Saliva, vaginal secretions—lower

concentrations

Importance of HIV as case study

3. Environment of viruses:

• Epidemiology of spread of AIDS

Importance of HIV as case study

3. Environment of viruses:

In U.S., new cases down throughout 1990’s, now on rise again—why?

• Complicated because HIV infects cells of immune system

• HIV doesn’t kill, just lowers body defenses as T-cell levels drop

Importance of HIV as case study

4. Immune Response:

Challenges

• Treat patients to prevent cell-to-cell infection by virions within body

• Stop spread of virions from person to person (role of sex education, condoms, status of women)

• Develop a vaccine—why so difficult (by end of this unit understand is goal!)