Immunodeficiency Pt. 2

Question 1

gag?

HIV

Answer 1

Core proteins and matrix proteins

Question 2

pol?

HIV

Answer 2

Reverse transcriptase, protease, and integrase enzymes

Question 3

env?

HIV

Answer 3

Transmembrane glycoproteins

• gp120 bind CD4 and CCR5
• gp41 required for virus fusion and internalization

Question 4

HIV receptor:
Co-receptors:
M-tropic virus:
T-tropic virus:

Answer 4

• CD4
• chemokine receptors CCR5 CXCR4
• infect macrophages, DCs, some T cells via CCR5 (early stage)
• infect T cells via CXCR4 (late stage)

Question 5

tat?

HIV

Answer 5

Positive regulator of transcription

Question 6

rev?

HIV

Answer 6

Allows export of unspliced and partially spliced transcripts from nucleus

Question 7

What molecules affect the progression of HIV to AIDS?

Answer 7

HLA-B and KIR3DL1/S1

• affect HIV activities of CD8 T cells and NK cells

Question 8

Antigenic drift leads to:

Antigenic shift lead to:

Answer 8

• Epidemics

- Pandemics

Question 9

Some infections with lots of antigenic variation:

Answer 9

• African trypanosomes (sleeping sickness)
• Neisseria gonorrhea
• Salmonella tryphimurium

Question 10

Why are neuron cells a favored place for viruses to “hide”?

Answer 10

They have very few MHC I

EBV hides in B cells

Question 11

How does Vaccinia inhibit humoral immunity?

Answer 11

Virally encoded complement control protein

- Inhibit complement activation of infected cell

Question 12

How do Vaccinia and Rabbit myxoma virus inhibit the inflammatory response?

Answer 12

Virally encoded soluble cytokine receptor (IL-1, TNF, IFN-gamma homologs)
- Block effects of cytokines by inhibiting their interaction with host receptors

Question 13

How do HSV and Cytomegalovirus block antigen processing and presentation?

Answer 13

Inhibition of MHC class I expression
- Impairs recognition of infected cells by cytotoxic T cells

Question 14

How (else) does HSV block antigen processing and presentation?

Answer 14

Inhibition of peptide transport by TAP
- Blocks peptide association with MHC class I

Question 15

How does EBV immunosuppress the host?

Answer 15

Virally encoded cytokine homolog of IL-10

- Inhibit Th1 lymphocytes; reduce IFN-gamma production

Question 16

How does this bacteria subvert the immune system?

Mycobacterium leprae

Answer 16

Induces Th2 response to evade Th1 CMI response

Question 17

How does this bacteria subvert the immune system?

Mycobacterium tuberculosis

Answer 17

Prevent fusion of phagosomes with lysosomes

Question 18

How does this bacteria subvert the immune system?

Listeria monocytogenes

Answer 18

Escapes phagosomes

Question 19

How does this bacteria subvert the immune system?

Treponema pallidum

Answer 19

Coats itself with human protein

Question 20

How does this bacteria subvert the immune system?

Staphylococci

Answer 20

Produces superantigens (SEB and TSST-1)

Question 21

How do superantigens increase T cell response?

Answer 21

Bind MHC so non-specific T cell activation and cytokine storm

Question 22

What is SSLP7 and how does it work?

Answer 22

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).

Question 23

How is fetal cell immunogenicity reduced?

Answer 23

Trophoblasts (fetal cells) don’t express MHC I or II

Question 24

What else goes on in the mother to reduce effects of the immune system during pregnancy?

Answer 24

Secretion of alpha-fetoprotein, IL-10, and TGF-beta to suppress the immune system.

Also, inhibition by Treg cells.

Question 25

What cells play a role in implantation and early invasion of the trophoblast?

Answer 25

NK cells