Immunodeficiency Pt. 2 Flashcards
gag?
HIV
Core proteins and matrix proteins
pol?
HIV
Reverse transcriptase, protease, and integrase enzymes
env?
HIV
Transmembrane glycoproteins
- gp120 bind CD4 and CCR5
- gp41 required for virus fusion and internalization
HIV receptor:
Co-receptors:
M-tropic virus:
T-tropic virus:
- CD4
- chemokine receptors CCR5 CXCR4
- infect macrophages, DCs, some T cells via CCR5 (early stage)
- infect T cells via CXCR4 (late stage)
tat?
HIV
Positive regulator of transcription
rev?
HIV
Allows export of unspliced and partially spliced transcripts from nucleus
What molecules affect the progression of HIV to AIDS?
HLA-B and KIR3DL1/S1
- affect HIV activities of CD8 T cells and NK cells
Antigenic drift leads to:
Antigenic shift lead to:
- Epidemics
- Pandemics
Some infections with lots of antigenic variation:
- African trypanosomes (sleeping sickness)
- Neisseria gonorrhea
- Salmonella tryphimurium
Why are neuron cells a favored place for viruses to “hide”?
They have very few MHC I
EBV hides in B cells
How does Vaccinia inhibit humoral immunity?
Virally encoded complement control protein
- Inhibit complement activation of infected cell
How do Vaccinia and Rabbit myxoma virus inhibit the inflammatory response?
Virally encoded soluble cytokine receptor (IL-1, TNF, IFN-gamma homologs)
- Block effects of cytokines by inhibiting their interaction with host receptors
How do HSV and Cytomegalovirus block antigen processing and presentation?
Inhibition of MHC class I expression - Impairs recognition of infected cells by cytotoxic T cells
How (else) does HSV block antigen processing and presentation?
Inhibition of peptide transport by TAP - Blocks peptide association with MHC class I
How does EBV immunosuppress the host?
Virally encoded cytokine homolog of IL-10
- Inhibit Th1 lymphocytes; reduce IFN-gamma production
How does this bacteria subvert the immune system?
Mycobacterium leprae
Induces Th2 response to evade Th1 CMI response
How does this bacteria subvert the immune system?
Mycobacterium tuberculosis
Prevent fusion of phagosomes with lysosomes
How does this bacteria subvert the immune system?
Listeria monocytogenes
Escapes phagosomes
How does this bacteria subvert the immune system?
Treponema pallidum
Coats itself with human protein
How does this bacteria subvert the immune system?
Staphylococci
Produces superantigens (SEB and TSST-1)
How do superantigens increase T cell response?
Bind MHC so non-specific T cell activation and cytokine storm
What is SSLP7 and how does it work?
Staphylococcal superantigen-like protein 7
Bind with C5 to IgA that is on a bacterial cell. This prevents phagocytosis of the bacteria (the phagocyte can’t recognize the IgA).
How is fetal cell immunogenicity reduced?
Trophoblasts (fetal cells) don’t express MHC I or II
What else goes on in the mother to reduce effects of the immune system during pregnancy?
Secretion of alpha-fetoprotein, IL-10, and TGF-beta to suppress the immune system.
Also, inhibition by Treg cells.
What cells play a role in implantation and early invasion of the trophoblast?
NK cells