Exam Questions For 4 17

Q. Give an example of how a virus can avoid interferon effects.
A. The influenza virus covers its dsRNA with a protien, so the dsRNA is not detected (RNases and protein kinases made by interferons are only activated in the presence of dsRNA).
Pox virus stops phosphorylation cascade that leads to antiviral gene expresssion
HIV makes VIF—> binds to cytosine deaminase which causes the complex to be tagged with ubiquitin and degraded

Subtractive Immunization: information from Melissa's paper can be found under discussion-notes!

1. Which of the following are differences between Type-1 and Type-2 interferons?
a. Type-1 interferons only recognize viral motifs
b. Type-2 interferons are located in vacuoles
c. Type-2 interferons recognize a lot of different pathogens
d. Type-1 and Type-2 have similar activation mechanisms
ANSWER - a,c

2. Which of the following are differences of classical and non-classical MHCs?
a. Non-classical MHCs are antigen loading proteins
b. Classical MHCs are composed of alpha and beta chains
c. Classical MHCs present antigens to both CD4+ and CD8+ T-cells
ANSWER - a,c

3. Put the steps of an immature dendritic cell changing to a mature, activated dendritic cell
a. dendritic cell detects microbial components
b. immature dendritic cell sampling environment with phagocytosis and macropinocytosis
c. expression of B7 co-stimulation of T-cells
d. dendritic cell increases phagocytosis and macropinocytosis
e. increase of MHCII and some MHCI on dendritic cell
f. T-cells know dendritic cell is presenting foreign antigen and is activated
ANSWER - b,a,d,e,c,f

4. What is not a step in RNAi?
a. cell recognizes dsRNA and makes Dicer enzyme
b. dsRNA is ubiquinated
c. viral dsRNA is cleaved into small pieces
d. inhibits viral gene expression
ANSWER - b. i would say D is also not a step, it is more of the overalll outcome of RNAi

5. Which statements are true of dendritic cells?
a. immature DC are globular in shape
b. B7 on a mature DC tells the T-cell that this DC is presenting a self antigen
c. Activated, mature DCs lead to an increase in phagocytosis and micropinocytosis
d. They mature in the spleen

6. Which are true for positive selection for T-cell receptors
a. weak attraction to self antigens
b. strong attraction to self antigens
c. weak attraction to foreign antigens
d. strong attraction to foreign antigens
ANSWER: a, d
7. Which are true for negative selection for TCRS
a. weak attraction to self antigens
b. strong attraction to self antigens
c. weak attraction to foreign antigens
d. strong attraction to foreign antigens
Answer: b,c
8. What are differences between TCR's and MHCs
a. There are a possibility of 10^13 different kind of T-cells
b. MHC's are the same throughout your body
c. TCR's have both alpha and beta chains
d. MHC's variable come allele recombination from birth
Answers a,b,d
9. What is true of cytosine deaminases
a. changes cytosine into uracil
b. helps cleave dsRNA
c. can be stopped by HIV vif protein
d. its goal is to cause mutation so a virus can no longer replicate
Answers: a,c,d

10.Kit Snicket wanted to do subtractive immunization to produce monoclonal antibodies against RyanO-AG. First, a mouse was injected with RyanO-AG periodically for several weeks to create memory-T-cells against RyanO-AG. But they could also be against RyanO-Beau, which is very similar in structure. To select against RyanO-Beau they injected a mouse with cyclophosphamide and RyanO-AG. Kit Snicket then cuts open the lymphocytes of the mouse to retrieve the RyanO-AG antibodies via flow cytometry & Elisa… No RyanO-AG antibodies are present… what did Kit Snicket do wrong?

ANSWER. Cyclophosphamide kills proliferating cells. To select for RyanO-AG antibodies Kit should have coupled cyclophosphamide with RyanO-Beau to kill off all the T-cells specific to RyanO-Beau but not RyanO-AG and produce monoclonal RyanO-AG.
Wow willie wow

11. What are the sim/diff between Western, Northern, & Southern blotting?

12. Sequence these events in order for the loading of a MHC 1 molecule:
a. Proteosomes interact with ER
b. Proteosomes cut up microbe into smaller fragments
c. mRNA of MHC molecule is translated at ribosome
d. MHC 1 with peptide bleb off of ER in vacuole
e. Chaperone proteins bind to peptide binding groove
f. Microbial peptide is bound to peptide binding groove
g. Antigen is expressed extracellularly via MHC 1
(answer: C, E, B, A, F, D, G)

13. Which of the following are differences between MHC I and MHC II loading of a peptide?
a. both need a peptide bound to the peptide-binding-groove to be stable
b. a vacuole containing pathogen peptides fuses with a vacuole from the lumen of the ER containing MHC II
c. peptides that are loaded onto MHC I are located in the cytoplasm
d. both require a clamp loading protein

What are the effects of interfuerons|?
a. breaks down rna through the use of RNase
b. induce apoptosis trough p53 pretein synthesis
c. use mx proteins to stop translation and stop blebbing
d. recruit cytoxic CD4+ t-cells to infected cell to induce apoptosis

Answers: a,c

HPV 16 and 18
a. are strains of the Human Polenoma Virus
b. Make protein called E6, that causes the ubiquitinzation of p53
c. makes vif, a portein that is used to avoid apoptosis
d. makes transcrption frtactors for bcl-2.

Answers a,b,d

What are characteristics of CD8+ t-cells?
a. they are also called t- helper cells
b. are in volved in rejection of organ transplants in some patients
c. use fas, perporins and granuzymes to kill virally iuinfected cells
d. The preferentially intereact with Dendridic cells over other cells

answers b,c

What are similarities between MHC I and MHC II molecules?
a. contain at least 2 beta chains.
b. both alpha and beta chains interact with the cell membrane.
c. have consensus binding
d. present antigens
Answer: d

TH1- recruits phagocytic cells in deep tissues, realease IFN-gamma, stimulate t cells to produce IgG
TH2 - recruits eosinophils, basophils, mast cells, macrophages in epithelia, ILs.

Herd Immunity: a few people who chose not to get immunized in a population that have been immunized. The few people believe they are safe this way because they will never come in contact with diseases.

Adjuvant is an ingrediant in vaccines that annoy inflammation responses, otherwise the body may reject the vaccine.

Choose the correct mechanisms that these viruses use to help stay alive.
a. The pox virus stops the Jak stat pathway
b. HIV uses vif proteins
c. The Flu virus covers it dsRNA
d. HPV makes protein E6 that binds to p53
Answers: a,b,c,d
What properties of CD8+T-cells are false
a. Interacts with MHC II
b. can recognize foreign MHC I
c. kills "virally infected cell" from its view
d. Is not part of the problem of host vs. graft disease
Answers: a, d

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