Colds and influenza

Question 1

What is the first line defence against a viral infection?

Answer 1

Production of interferons

Question 2

The binding of antibodies is first line defence against a viral infection. True or false?

Answer 2

False - second line

Question 3

The T-cell recognition of viral antigens is the final part of defence against viral infections. True or false?

Answer 3

True

Question 4

What is meant by cell-mediated immunity?

Answer 4

The recognition and killing of virus and virus-infected cells by leukocytes
Production of different cytokines by the cells when stimulated by virus

Question 5

How does granzyme B kill cells?

Answer 5

Apoptosis

Question 6

Antigen recognition by NK cells is MHC restricted. True or false?

Answer 6

False

Question 7

Antibody neutralisation is most effective when the virus is present in large fluid spaces e.g. serum or on moist surfaces e.g. GIT. True or false?

Answer 7

True

Question 8

What is the function of HA in influenza?

Answer 8

HA is a surface protein that function as a receptor binding site and attaches to sialic acid containing receptors on the host cells

Question 9

What is the function of NA in influenza?

Answer 9

It cleaves off sialic acid from the cell receptor for the influenza virus so virions can be released from infected cells and spread to other host cells

Question 10

What is the role of the M1 protein in influenza?

Answer 10

Has a significant role in virus assembly

Question 11

What is the role of M2 protein in influenza?

Answer 11

Functions as a H+ ion channel so they control pH in the golgi complex during HA synthesis and disassembly

Question 12

Antibodies directed against HA are associated with vaccine protection. How do these antibodies work?

Answer 12

They block the binding of the virus to host cell receptor or block fusion of the virus with host cell membrane

Question 13

How do NA inhibitors work?

Answer 13

Antibodies directed against NA do not prevent infection but limit the release of virus from infected cells

Question 14

NA inhibitors are anticipated to reduce the duration of the illness by 1-3 days and reduce the severity and risk of transmission. True or false?

Answer 14

True

Question 15

What do antibodies against the M2 protein do?

Answer 15

They interfere with virus assembly or constrain proton transport

Question 16

Prevalence is due to the ease by which the virus can spread through a susceptible population. True or false?

Answer 16

True

Question 17

What is the difference between antigenic shift and antigenic drift?

Answer 17

Antigenic drift is where there is a small mutation in HA or NA whereas antigenic shift is where there is a major change due to genetic reassortment of two different viral strains creating a completely new virus