Retroviruses II Flashcards
1
Q
HIV Transmission
- How infectious is it?
- How is it not spread?
- What body fluids is it found in?
- What cells are infected?
A
- not particularly infectious/contagious
- not by respiratory, alimentary, or vector routes
- plasma, semen, vaginal fluids
- Peripheral blood mononuclear cells, semens, vaginal/cervical fluid
2
Q
HIV Transmission
- What increases HIV transmission?
- How stable is HIV in the enviroment?
- What are some ways to reduce HIV infectivity in the environment?
A
- Genital ulcer disease
- not stable
- air drying, heating, 10% bleach, 70% alcohol, pH extremes (10), detergents
3
Q
HIV strain variation
- What clade predominates in US and Europe?
- What clade predominates in Thailand?
- What clade is spreading in Africa?
- What is the trouble with developing vaccines?
A
- B
- E
- C
- HIV is genetically plastic, hard to make vaccines against it
4
Q
HIV Structure
- Surface proteins
- Proteins in the core
- Genome
A
- gp120 and gp41
- ribonuclease H, protease, integrase
- diploid ssRNA
5
Q
HIV Infection
- What 2 cell types can it infect?
- How does it infect each one?
- What can give immunity to HIV?
A
- T cells and macrophages
- gp 120 variant can bind CXCr4 on CD4+ T cells
gp 120 variant can bind CCr5 on Macrophages - increased Beta-chemokines that bind CCr5 can block the receptor and lead to protection from infection
6
Q
HIV infection
- What does HIV require to infect cells?
- What if a pt doesn’t have this?
A
- CCr5 to infect macrophages
2. pt does not get HIV/AIDS
7
Q
HIV pathogenesis
- What kind of replication does HIV go through?
- What extra stuff does HIV have?
A
- classic retroviral replication program w/ notable complexities
- accessory genes controlling pathogenicity: tat and rev
8
Q
HIV genes
- What does tat do?
- What does rev do?
A
- transcription activator
2. allows newly synthesized mRNA to move quickly into the cytoplasm
9
Q
HIV pathology
- What does it do to CD 4+ cells?
- What is seen in lymph node? Why?
- What 2 words cahracterize HIV infection?
- Why is HIV infection of CD4 T cells dangerous?
A
- forms highly vacuolated blasts that don’t last long
- multi-nucleated giant cells; HIV induces CD4+ cells to express gp120 –> fusion
- robust and cytolytic
- CD4 cells regulate the immune system; allows virus to evade/modify immune responses
10
Q
Three Stages to HIV induced disease
A
- Infection
- Seroconversion
- AIDS
11
Q
Serology of HIV
- What occurs early to CD4 cells?
- What happens then?
- What happens to precipitate AIDS?
A
- transient decline in CD4 cells
- rebounds, but CD4 cells don’t ever recover to pre-infection levels
- Drop in CD4 cells
12
Q
Serology of HIV
- What happens to viral load early? middle? late?
- What happens to Ab to HIV Env and p24?
- What happens to HIV-specific CTL?
A
- large increase early; falls middle; rises as AIDS sets in
- increase in Ab early that stays high, then drops as AIDS sets in
- rises early and stays high, then drops as AIDS sets in
13
Q
- What are the three ways HIV can progress?
2. What are the 3 main parts of the HIV progression?
A
- Typical (normal, 12+ years); Rapid Progressor (–> AIDS w/in months); Nonprogressor (stays clinically latent for years)
- Acute Infection, Clinical Latency, Clinical Disease (AIDS)
14
Q
Acute Infection
- What disease does it look like?
- When is it observed?
- Symptoms
- What happens to T cells?
A
- mono-nucleosis
- 3 weeks after initial infection
- fever, fatigue, swollen lymph nodes; symptoms can vary considerably; most don’t seek medical care for these symptoms
- T cell levels drop, may rebound slightly, but rarely reach pre-infection levels
15
Q
Clinical Latency
- How long does it last?
- Clinical Manifestations
- What is the virus doing?
- What can be detected in blood?
A
- 8-12 years
- few, if any
- not latent, high levels of viral replication;
- live, infectious virus