Immunology

Question 1

What is the primary animal model for immunology research?

Answer 1

Inbred mouse strains

Question 2

What are the primary lymphoid organs? What are their functions?

Answer 2

Thymus and bone marrow. Hematopoiesis and B- and T- lymphocyte development.

Question 3

What are the secondary lymphoid organs? (3) What is their function?

Answer 3

Lymph nodes, spleen, and intestinal Peyer’s patches.
Immune response initiation.

Question 4

What are tertiary lymphoid organs? What are two examples?

Answer 4

Form in response to a insult or microbial exposure in a solid organ.
GALT - Gut-associated lymphoid tissue
BALT - Bronchus-associated lymphoid tissue

Question 5

What does the innate immune system respond to? How do they respond to these structures?

Answer 5

Pathogen-associated molecular patterns (PAMPs)
Pattern recognition receptors (PRRs)

Question 6

List examples of PAMPs (4)

Answer 6

LPS, bacterial flagellin, RNA, and non-methylated DNA

Question 7

List examples of PRRs (3)

Answer 7

Toll-, RIG-, and NOD-like receptors

Question 8

List cells belonging to the innate immune system (3)

Answer 8

Monocytes/macrophages, granulocytes and dendritic cells, and innate-like lymphocyte populations 1, 2, and 3 (includes NK cells)

Question 9

What cells belong to that adaptive immune system? What differentiates their receptors?

Answer 9

T- and B- lymphocytes. Have highly antigen-specific receptors.

Question 10

What B cells are innate-like? Why?

Answer 10

B cells of B-1 lineage and gamma delta T cells. Innate-like as they respond in an innate-like manner, despite having a rearranged antigen receptor.

Question 11

How are leukocytes identified?

Answer 11

Monoclonal antibodies against cell surface receptors.

Question 12

How are levels of different leukocytes measured? How are receptor names referred to?

Answer 12

Flow cytometry. Identification leads to assignment of receptor name as CD (cluster of differentiation).

Question 13

List the two T lymphocytes, their MHC class, and function.

Answer 13

CD4 = T helper, MHC Class II, B-cell activation
CD8 = Killer T, MHC Class I, cytotoxic

Question 14

What are activated B cells known as? What do they produce?

Answer 14

Plasma cells, antibodies

Question 15

What Ig is only found on the surface of mouse B cells?

Answer 15

IgD

Question 16

What are the subtypes of IgG? (4)

Answer 16

1. IgG1
2. IgG2a/c
3. IgG2b
4. IgG3

Question 17

When is each Ig produced?

Answer 17

IgM - Short term, on initial exposure
IgG1 - Extracellular bacterial injection
IgG2a/c - Viral or intracellular bacterial
IgG2b and IgG3 = Carbohydrate or lipid antigen
IgE = Allergy or parasite
IgA = Mucosal surfaces

Question 18

What Ig is produced in highest amounts? Where is it produced, by which cells, and what is the functional form. Does the level in the serum reflect this?

Answer 18

IgA. Produced by plasma cells in the laminae propria of the mucosa and transported to the luminal surface in the dimeric form. Serum levels are low because IgA is released on mucosal surfaces.

Question 19

What are cytokines? When are they released? List examples (4)

Answer 19

Secreted signaling molecules involved in cell-cell communication.
Released on recognition of antigen by PRRs or T-cell receptors
Interleukins, tumor necrosis factors, interferons, and growth factors

Question 20

What are the functions of chemokines? How are they grouped?

Answer 20

Regulate cell trafficking to sites of antigen exposure and facilitate cell-cell contact by acting as chemoattractants.
Grouped according to number of cysteines and disulfide bonds.

Question 21

What does PRR engagement cause? By which cells?

Answer 21

Cytokine and chemokine response by first responders (innate cells, epithelial cells)

Question 21

What does the type of cytokine and chemokines released impact?

Answer 21

Dictates type of cells recruited and their differentiation and functions

Question 22

Outline the path from PRR engagement to CD4 differentiation.

Answer 22

PRR engagement causes dendritic cells touptake antigen, activate, and migrate to regional l.n. where they produced antigen on MHC to T cells and secrete cytokines induced by initial PRR response. The differentiation of CD4 cells is then directed towards a particular effector.

Question 22

Why are dendritic cells considered ‘bridges’?

Answer 22

They translate PRR signals into differentiation signals for T cells in lymph nodes

Question 22

What does the type of cytokines produced by CD4 cells impact?

Answer 22

Type of Ig isotype

Question 23

What are T follicular helper cells?

Answer 23

T cells that interact with B cells

Question 24

How does the cytokine profile induced by effector T-cell population compare to the innate immune response?

Answer 24

Mirrored response

Question 25

What do T regulatory cells release?

Answer 25

Inhibitory cytokines

Question 26

What is a bone marrow irradiation chimera? How long does it take for reconstitution? What is an advantage and disadvantage?

Answer 26

Lethal gamma irradiation is used to deplete hematopoietic stem cells followed by a bone marrow cell transfer. Takes 6 weeks to reconstitute.
Circumvents breeding Cre mice, but risk of off-target effects due to irradiation damage

Question 27

What is an advantage (2) and disadvantage (2) of injecting antibodies targeting specific cell populations?

Answer 27

Rapid and short-term
Need to identify antibodies and verify efficacy