This lesson explains how HIV affects the immune system, how it reproduces inside CD4 T lymphocytes, and how HIV infection is classified into stages. Understanding the viral life cycle also explains why antiretroviral drugs target different steps in replication.
Human immunodeficiency virus (HIV) is a virus that progressively damages the immune system, especially CD4 T lymphocytes, also called helper T cells. These cells help coordinate immune responses by signaling other immune cells to respond to infection. As their numbers decline, the body becomes less able to fight infections and some cancers.
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What is the difference between HIV and AIDS?
HIV is the virus that damages immune function. AIDS is the advanced stage of HIV infection, diagnosed with an AIDS-defining illness or a CD4 count below 200 cells/mm³.
What is the function of reverse transcriptase?
Reverse transcriptase makes a complementary DNA copy from HIV RNA, creating viral DNA that can later be integrated into a host cell.
What does integrase do?
Integrase inserts HIV DNA into the infected person's cellular DNA, enabling the host cell to produce viral components.
What does protease do in HIV replication?
Protease cuts long chains of viral proteins into mature, functional proteins needed to form infectious virus particles.
Why is the chronic stage not the same as viral inactivity?
During chronic infection, a person may have few symptoms, but HIV remains active, reproduces, and can still be transmitted.
Quiz questions
Which test detects HIV RNA directly and can identify infection earlier than antibody-based tests?Answer: A nucleic acid test.
How do cobicistat and ritonavir boost the blood levels of certain antiretroviral drugs?Answer: They inhibit CYP3A4 and reduce drug metabolism.
Which test is recommended before starting abacavir because of hypersensitivity risk?Answer: Testing for the HLA-B*5701 allele.
Which adverse effects are associated with protease inhibitors?Answer: Elevated lipids and glucose intolerance.
Why does antiretroviral therapy commonly combine drugs with different mechanisms?Answer: To suppress HIV at multiple steps and limit resistance.
Based on Pharmacology for Nurses by Tina Barbour-Taylor, Leah Mueller (Sabato), Donna Paris, Dorie Weaver (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.