11. HIV II Flashcards
(25 cards)
What is the relationship between HIV and the immune system?
HIV has one of the most complicated relationships with the immune system of any infectious agent.
Does the immune system mount a response against HIV?
Yes, the immune system mounts a powerful response against HIV.
What allows HIV to survive despite a strong immune response?
HIV’s special features allow it to survive and eventually destroy the immune system.
How does HIV reach lymph nodes?
HIV uses dendritic cells as ‘Trojan horses’ to reach lymph nodes.
What role do dendritic cells play in HIV infection?
Dendritic cells patrol mucosal tissues, pick up pathogens, and facilitate HIV spread to CD4+ T cells.
What is the significance of filopodia in HIV infection?
Infected dendritic cells extend filopodia with virus at tips, facilitating ~800 DC-T cell interactions per hour.
What happens to CD4+ T cells during HIV infection?
There is a progressive depletion of CD4+ T cells and disruption of lymph node architecture.
What is hypergammaglobulinemia?
It is a paradoxical increase in total serum IgG observed in HIV infection.
What is the immune response to HIV?
Strong antibody response to viral proteins (gp120, p24) and a powerful CD8+ cytotoxic T-cell response.
What percentage of the virus is eliminated by the immune response?
> 99% of the virus is eliminated but complete clearance is never achieved.
What occurs during the ‘latent’ phase of HIV infection?
The virus continues active replication with 10-100 times more productively infected cells in lymph nodes than in blood.
What are the virus evasion strategies against the immune system?
- High replication rate
- Proviral latency
- High mutation rate
- Targeting of CD4+ T cells
What are the mechanisms of CD4+ T cell death?
- Direct viral lysis
- Antibody-mediated destruction
- CD8+ T cell killing
- Pyroptosis
What is pyroptosis?
A highly inflammatory form of cell death that occurs in CD4+ T cells during HIV infection.
How does pyroptosis contribute to CD4+ T cell depletion?
Inflammation attracts more CD4+ T cells, creating a vicious cycle.
What are the three main types of drugs used in Antiretroviral Therapy (ART)?
- Nucleoside/nucleotide analogue reverse transcriptase inhibitors
- Non-nucleoside reverse transcriptase inhibitors
- HIV protease inhibitors
What is the first anti-HIV drug?
AZT (zidovudine), introduced in 1987.
What are the limitations of ART?
- Toxic side effects
- Complicated medication regimens
- Expensive treatment
- Suppresses but doesn’t eliminate virus
- Development of resistance
What new therapeutic approaches are being explored for HIV?
- Targeting viral accessory proteins
- Novel chemical drugs like PA-457
- Caspase-1 inhibitors to block pyroptosis
What are the challenges in HIV vaccine development?
- Multiple viral subtypes and variants
- High mutation rate
- Uncertainty about which immune responses to target
- Complex glycosylation of gp120
What are the two types of vaccines considered for HIV?
- Prophylactic vaccines
- Therapeutic vaccines
What is a potential microbicide for preventing HIV transmission?
Glycerol monolaurate blocks inflammatory process and is applied as a vaginal gel.
What is the impact of HIV over the past 40 years?
HIV has killed over 43 million people.
What is the current most effective approach to managing HIV?
Antiretroviral Therapy (ART).
