Immunology Exam 1 Practice Questions

Front 1

List TWO differences between the innate and adaptive immunity

Back 1

Time to activation: (innate, fast; adaptive, slow) [2 points]Surface receptors: (innate, invariant and broad recognition; adaptive, variable andprecise recognition) [2 points]Other answers are fine also, including but not limited to:Memory and clonal expansion for adaptive immunity onlyInnate immunity remain constant and adaptive immunity improves over time.

Front 2

List TWO central lymphoid organs AND TWO peripheral lymphoid organs?

Back 2

Central: bone marrow, thymus [1 point] Peripheral: spleen, lymph node [1 point]

Front 3

What is the consequence if an infant is born without a spleen?

Back 3

Unable to mount an adaptive response against a pathogen in the blood stream. [1 point]Susceptible to bloodstream infections [1 point]

Front 4

What are the THREE barriers that compose the body’s first line of defense?

Back 4

Physical, chemical and microbiological barriers

Front 5

Describe the molecular property of defensins. What is their function and how isnonspecific damage to host cells prevented.

Back 5

They are small amphipathic molecules half positively charged and half hydrophobic.They insert into microbe surface to interfere with membrane integrity.They don’t insert into the host cell membrane as well as to the microbial surfaces

Front 6

Describe the major host defense mechanisms against:

Extracellular pathogens

Back 6

Complement, antibody, antimicrobial peptides and enzymes [3 points]

Front 7

Describe the major host defense mechanisms against:

Bacterial toxins:

Back 7

Antibody [2 points]

Front 8

Describe the major host defense mechanisms against:

Intracellular cytosolic pathogens:

Back 8

Cytotoxic T cells or NK cells induced killing of infected cells [2 points]

Front 9

Describe the major host defense mechanisms against:

Intracellular vesicular pathogens:

Back 9

Macrophage activation by T helper cells [2 points]

Front 10

Describe the severity of the symptoms in the same adult during the three infections withthe same pathogen and WHY. (initial, protective, memory)

Back 10

Initial immune response: (2 points)Usually severe, it takes time for the adaptive immunity to activate and control the infection

Protective immunity: (2 points)Unapparent, there are enough activated adaptive immune cells to eliminate the pathogenwithout causing any noticeable symptoms.Immunological memory: (2 points)Usually mild or even unapparent, the immune system is quickly activated to control theinfection

Front 11

What are the 3 mechanisms of complement-mediated clearance of bacteria?

Back 11

Opsonization [1 point]Inflammation [1 point]Attack complex formation [1 point]

Front 12

Describe the result of factor I deficiency

Back 12

Alternative pathway of the complement cascade is uninhibited and consumption of C3 isgreatly accelerated. [1 point]Defective in opsonization and frequent infections. [1 point]

Front 13

In the paper discussed in class, survival of different knock out mice to West Nile virusinfection is shown in the following graph (left). Draw the predicted survival curve of fB-/-,C3-/-, C4-/- and C1q-/- in the graph (right) when the knock out animals are infected witha virus that is only controlled by the alternative pathway.

Back 13

fB-/- and C3-/- will have reduced survival, C4-/- and C1q-/- will be similar to the wild-type.

Front 14

Outline the course of the immune response which leads to the activation of the adaptiveimmunity after a pathogen breaches the epithelial barrier [List the changes in immune cells,blood vessels, the key molecules and the circulation system the cells travels with. End when theadaptive immunity is activated.]

Back 14

1. The pathogen will first encounter macrophages. [1 point] Macrophage phagocytose thepathogen. [1 point] and release cytokines and chemokines [1 point] through theactivation of the pattern recognition receptors. [1 point]2. Endothelium is activated to express adhesion molecules to allow leukocytes recruitment. [1point] The blood vessel are more preamble which allow the serum complement componentsto enter the tissue. [1 point] Microvessels are clotted to prevent the spreading of thepathogen. [1 point] The fluid in the tissue carrying the pathogen is drained into peripherallymph nodes. [1 point]3. Neutrophils are recruited to control infection [1 point]4. Monocytes and recruited and they differentiate into macrophages and dendritic cells. [1 point]5. Dendritic cells are activated by the cytokines [1 points] and they travel to the lymphnodes through lymphatics [1 point ] and present antigen in the lymph node [1 points](activated dendritic cells travel to lymph nodes and present antigen to T cells)6. Activation of adaptive immunity [1 point] such as cytotoxic T cell activation and antibodyproduction

Front 15

Give an example of a membrane bound PRR and its ligand.

Back 15

TLR4 and LPS; TLR3 and dsRNA; TLR7 and ssRNA; TLR5 and flagelin, etc

Front 16

. Give an example of a cytosolic PRR and its ligand.

Back 16

RIG-1 and viral RNA; NOD and bacterial ligands; AIM and dsDNA, etc

Front 17

What is the consequence of the activation of a PRR.

Back 17

Cytokine secretion, phagocytosis

Front 18

True or False: PRR only recognize pathogen associated molecular patterns.

Back 18

false

Front 19

Which cells secret type I interferons?

Back 19

Viral infected cells

Front 20

What is the function of type I interferons? Give a general function (1 point) and three moredetailed molecular mechanisms

Back 20

Anti-viral response in self and neighbors. [1 point]

1 point for each but no more than 3 points:Restrict viral replication in infected cells

Enhance MHC expression in all cells

Enhance antigen presentation

Induce chemokine to attract more leukocytesActivates NK cellsActivates dendritic cells and macrophages

Front 21

Which cells secret Interferon-γ?

Back 21

Activated T cells

Front 22

What is the function of Interferon-γ?

Back 22

Activates infected macrophage to kill intravascular pathogens

Front 23

Describe the four steps and the molecules that are involved in neutrophil recruitment fromthe blood to the infected tissue.

Back 23

1. Rolling, mediated with selectin molecules [2 points]2. Tight adhesion. [1 point]Integrin activated by the signal from chemokine receptor [1 point]Tight adhesion of integrin with ICAM on endothelium [1 point]3. Transendothelial migration or diapedesis [1 point]4. Migration or chemotaxis in tissue, up the cxcl8 gradient [2 points]

Front 24

Extra Credit Question - Original Antigenic Sin.Predict the antibodies generated in the same individual (8 points).

Infection at 2 year old with a virus carrying ABCD antigens:

Infection at 10 year old with a virus carrying ABEF antigens:

Infection at 20 year old with a virus carrying EFGH antigens:

Infection at 30 year old with a virus carrying AEGI antigens:

Back 24

Infection at 2 year old with a virus carrying ABCD antigens: ABCD [2 points]

Infection at 10 year old with a virus carrying ABEF antigens: AB [2 points]Infection at 20 year old with a virus carrying EFGH antigens: EFGH [2 points]This is like a new infection.Infection at 30 year old with a virus carrying AEGI antigens: AEG [2 points]Memory cells generated during the previous two infections will all get activated.