Exam 3: Dr. Pinchuk Evasion and Subversion

Question 1

What is protective immunity to streptococcus pneumoniae like?

Answer 1

Serotype-specific

Question 2

What does each stereotype of streptococcus pneumoniae cause?

Answer 2

A primary immune response

Question 3

What is the most important source of long-term protective immunity to many infectious diseases?

Answer 3

Antibodies directed against macromolecules on the surface of pathogens

Question 4

How do some species evade long-term protection?

Answer 4

By existing in numerous different strains, which differ in the antigenic macromolecules on their outer surfaces

Question 5

What does mutation allow influenza virus to do?

Answer 5

Escape from immunity

Question 6

What results in antigenic drift?

Answer 6

Point mutations in the hemagglutinin and neuraminidase viral genes

Question 7

What does recombination allow influenza virus to do?

Answer 7

Escape from immunity

Question 8

What is antigenic shift?

Answer 8

Appearance of the new antigens as a result genetic recombinations between two or more viral strains

Question 9

What does antigenic variation by African trypanosomes allow them to do?

Answer 9

Escape from adaptive immunity

Question 10

What uses persistence by hiding from the immune responses?

Answer 10

Herpesviruses persist in a latent state in the trigeminal region
Ncp BVDV

Question 11

Look at sabotage or subversion of immune defense mechanisms

Answer 11

Look at sabotage or subversion of immune defense mechanisms

Question 12

What are survival strategies of intracellular pathogens?

Answer 12

Interfere with antigen uptake mechanisms thus avoiding fast and effective antigen recognition
Create their own vesicle environment which prevents the binding to MHC and their presentation to T cells
Prevent fusion of the phagosomes with lysosomes thus protecting themselves from the lysosomal enzymes, survive and flourish within the cells of vesicular system
Escape from the phagosome into the cytosol, grow and replicate

Question 13

What is toxoplasma gondii?

Answer 13

Highly successful obligate intracellular parasite that can invade and replicate in almost all nucleated cells of warm-blooded animals

Question 14

What does toxoplasma gondii do?

Answer 14

Regulates immune activation and host cell effector mechanisms by specific parasite effector proteins

Question 15

What are toxoplasma effectors?

Answer 15

Master regulators of the pro-inflammatory response

Question 16

What do the combination of the effectors of toxoplasma gondii work to maintain?

Answer 16

An optional parasite burden in different hosts to ensure parasite transmission

Question 17

What are the target cells for leishmania?

Answer 17

Macrophages

Question 18

How are canine vector-borne diseases characterized by?

Answer 18

The unique three-way interaction between the infectious agent, the vector, and the host immune system

Question 19

What do the effects on host immunity promote?

Answer 19

Th2 regulated humoral responses above the host protective Th1-regulated cellular response

Question 20

What are the 2 types of immunity developed with leishmania?

Answer 20

Sterilizing immunity

Chronic infection

Question 21

What is sterilizing immunity prevented by?

Answer 21

T cells with regulatory function

Question 22

Look at leishmania picture

Answer 22

Look at leishmania picture

Question 23

What do viral replication and life cycle depend on?

Answer 23

The metabolic and biosynthetic processes in the host cells

Question 24

What are the viral self-defense strategies?

Answer 24

Capture of cellular genes encoding cytokines and receptors and diverting the immune response
Synthesis of proteins that inhibit complement fixation
Synthesis of proteins that inhibit antigen processing and presentation

Question 25

What are the most powerful T cell mitogens ever discovered?

Answer 25

Superantigens

Question 26

What do superantigens do?

Answer 26

Stimulate the T lymphocytes in an uncontrolled manner resulting in fever, shock, and death

Question 27

What does T cells being activated by superantigens result in?

Answer 27

Massive systemic release of pro-inflammatory cytokines, such as TNF-α and IL-1β, and T cell mediators, such as IL-2m which can lead to fever and shock

Question 28

Are superantigens presented as peptides in the peptide-biding groove of MHC II molecules?

Answer 28

No

Question 29

What do superantigens bind to?

Answer 29

MHC II molecules without being processed previously

Question 30

What happens in the superantigen mode of stimulation?

Answer 30

Does not prime an adaptive immune response specific for the antigen
Stimulates large numbers of T cells
Causes a massive production of cytokines by CD4 T cells
Contributes to microbial pathogenicity

Question 31

What are examples of superantigen-mediated diseases?

Answer 31

Toxic shock syndrome
Food poisoning
Mastitis

Question 32

Can immune responses contribute to disease?

Answer 32

Yes

Question 33

For some infectious disease, what is all pathology due to?

Answer 33

Immune response

Question 34

How do helminths go viral?

Answer 34

Cellular signals during helminth infections can skew the immune response to favor viral spreading

Question 35

What does a helminth reaction activate?

Answer 35

Th2 cells to release IL-4 and IL-3

Question 36

What does the ideal immune response do?

Answer 36

Terminates infection before the pathogen damages tissues or saps the body’s resources

Question 37

What is the ideal situation for a pathogen?

Answer 37

The immune system does not interfere with growth and replication
Other parts of the body provide food and shelter