Reference no: EM1343280

Question 1: Cytopathic and non-cytopathic viruses elicit very different immune responses. The primary determining factor in the type of immune response to a viral infection is which of the following (select one)?Answer 

A.Initial inflammatory response to virus. 

B.Whether virus is first recognized by macrophages or dendritic cells 

C.Genome type (RNA or DNA) of virus 

D.Whether IgG or IgMantobodies are produced.

 

Question 2: Many viruses evade the actions of NK cells by producing viral homologue of the host [x] receptor.

 

Question 3: This phenomena occurs when memory T-cells specific for one virus are activated during infection by unrelated virus.

A.Systemic Inflammatory Response Syndrome 

B.Superantigens 

C.Antigen Presentation 

D.Transcytosis 

E.Heterologous T-cell Immunity

 

Question 4 Match the following immune system cell types with their role in fighting a viral infection

Answer                                                                         

Macrophages

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Dendritic Cells

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Helper T cells

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Cytotoxic T- Cells

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Natural Killer Cells

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Plasma B Cells

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Answer

A. Take up viral antigens in peripheral tissues present them to T-cells in the lymphoid organs

B. Cells that contain antigen specific cell surface receptors and produce soluble antibodies specific for viral antigens

C. Recognize and kill cells infected by viruses through recognition of specific viral antigens on surface of cell

D. Coordinate adaptive immune response by releasing cytokines, activation macrophages and stimulating B-cells to produce antibody.

E. Scavenger phagocytic cells that are a major source of inflammatory cytokines in innate immunity and also involved in antigen presentation.

F. Kill virus infected cells by recognizing the absence of MHC on surface of infected cells.

Question 6: Viruses are intracellular pathogens that can hide within a cell. The adaptive immune response responds to pathogens using antibodies and T-cells, neither which are capable of entering cells and directly recognizing the virus. Briefy, describe how the adaptive immune response is able to recognize a cell is infected and eliminate infected cells (Max 5-6 sentences)

Question 7 Which of the following are mechanims by which antibodies can inhibit a viral infection in humans (Select all that apply)?

Answer 

A.Bind to viral polymerase and inhibit its ability to replicate viral genome 

B.Bind to virus antigen and recruit non-specific cells such as macrophages or NK cells to engulf the virion or kill an infected cell.

 C.Recognition of alpha(1,3) galactose which inhibits fusion of enveloped viruses in higher primates 

D.Bind to viral capsid or viral receptor and sterically prevent binding to host cell receptor 

E.Bind to T-cells and stimulate reelease of cytokines

 

Question 9 Which of the following mechanisms would enable a virus to evade the immune response (select all that apply)?

Answer 

A.Virus downregulates expression of NK cell activating ligands 

B.Enhance production of perforins by CD8+ T-cells

C.Activation of NFkB transcription factor 

D.Inhibit expression of MHC Class I molecules on surface of cell. 

E.Inhibition of cellular proteasome pathways

 

Question 10: A recent paper suggests that a mechanism by which the influenza virus can evade the adaptive immune response is to kill influenza specific B-cells in the respiratory tract. Explain why this might aid an influenza infection. In addition, given what you have learned about viruses and the immune response, suggest a mechanism the virus could use to specifically kill B-cells (5-6 sentences max)..