Virus- HIV Flashcards
(36 cards)
Which continent has the highest incidence (and prevalence) of AIDS?
Africa
What are the three major routes of HIV transmission?
- Sexual contact
- Vertical (mother to newborn) transmission
- Parenteral
What is the most common mode of HIV transmission on a global basis?
Heterosexual contact
What type of virus is HIV?
Human retrovirus of the lentivirus family
What test is used to screen for HIV infection?
Enzyme-linked immunosorbent assay (ELISA) looks for AB to viral proteins; ↑ sensitivity.
What test is used to confirm HIV(+) screening results?
Western blot assay (high false negative within 2 months of infection); ↑ specificity
Which enzyme creates dsDNA from RNA for integration into host genome?
Reverse transcriptase (RT)
What test is used to monitor the effects of antiretroviral therapy?
HIV RT-polymerase chain reaction (RT-PCR) (measures viral load)
What is the strongest measure of disease progression in an HIV(+) patient?
CD4+ T-cell count
Name two key glycoproteins on the surface of the HIV viral envelope:
- gp41 (fusion)
2. gp120 (attachment) proteins; together = gp160
Name two key HIV viral core proteins:
- p24 (nucleocapsid)
2. p17 (matrix protein)
Name three key HIV retroviral enzymes contained in the core:
- RT
- Integrase
- Protease (all encoded by pol gene)
Which viral antigen peaks within 2 months of infection, then rises again years later?
p24
What are the two cell surface molecules to which gpl20 must bind?
- CD4
2. A chemokine receptor (CCR5 or CXCR4)
HIV infects which three cell types?
- CD4+T cells
- Monocytes/macrophages
- Dendritic cells
The induction of what cellular transcription factor during an immune response leads to activation of transcription of HIV proviral DNA?
Nuclear factor-kappa B (NF-KB)
Protease inhibitors of HIV prevent cleavage of the protein product of what viral genes?
Gag and pol genes
What are the three mechanisms by which HIV-infected CD4+ T cells are lost?
- HIV cytopathic effect
- Apoptosis
- HlV-specific cytotoxic T-cell killing
What are the three stages of HIV infection?
- Acute retroviral infection
- Chronic phase
- AIDS
What is the surrogate measure of viral load in an HIV(+) patient?
HIV-1 RNA
What is the strongest measure of disease progression in AIDS?
CD4+ T-cell count
Which tissues are the major reservoirs of HIV-infected T cells and macrophages in patients?
- Lymph nodes
- Spleen
- Tonsils
Which cell type in the brain is infected by HIV?
Microglial cells
List the major immune abnormalities in AIDS:
- Decreased number of CD4+ T cells
- Decreased T-cell function
- Polyclonal activation of B cells
- Altered macrophage function