Immune response to viruses

Question 1

Define immune response

Answer 1

normal protective mechanism – host recognizes infectious agent – tries to remove it

Question 2

What is the major difference between acute and chronic infection?

Answer 2

Acute infection – replication usually results in host immunity and shortly after, disease is terminated

Chronic infection – host immune response not enough to stop viral replication

Question 3

What do plasma cells do to the virus?

Answer 3

Neutralize the virus

Question 4

What does interferon do?

Answer 4

virus infected cells secrete it
prevents viral replication in other host cells by binding
enhances killing power of macrophages, NK, and cytotoxic T cells

Question 5

What has a higher titer, primary or secondary antibody response?

Answer 5

Secondary Ab response

Question 6

Is humoral or cellular immune response important in resolving viral infection?

Answer 6

Cellular

Question 7

What T lymphocyte eradicates viral infection?

Answer 7

CD8 – cytotoxic T cells

Question 8

T/F

viruses can use cytokines to their own advantage

Answer 8

True – certain viruses can
EBV: IL-10
Poxviruses: TNF
Poxviruses: IL-1 receptor

Question 9

What immunoglobulin is important at controlling viral infection at mucosal surface?

Answer 9

IgA

Question 10

What do complement do for immune response against virus?

Answer 10

enhance neutralization of virus

Question 11

What are 5 ways viruses evade immune recognition?

Answer 11

1. Induction of immunosuppression
2. Induction of immune tolerance
3. Destruction of antigen presenting cells
4. Inhibition of recognition by Ab
5. Inhibition of recognition by T cell mediated immune response

Question 12

How can a virus inhibit the recognition by T cell mediated immune response?

Answer 12

Infect cells lacking MHC-I (neurons)
Inhibit MHC function (adenovirus)
Downregulate viral protein expression
Induction of mutation in viral protein T cell epitopes

Question 13

How are virus induced immune complexes formed and what concern do they bring?

Answer 13

Ab interacts with virus or viral antigen in fluid phase –> virus antibody complex

glomerulonephritis
arteritis and choroiditis

Question 14

What are two ways virus induced autoimmune diseases?

Answer 14

Modulation of immune cells to present self antigen
Molecular mimicry (viral antigen looks similar to host) -- more common

Question 15

T/F

viruses are obligate intracellular parasites

Answer 15

True

Question 16

What are three ways we can protect new born animals from viral infection?

Answer 16

Maternal immunization
Colostrum replacers
Implications for immunization of young animals