Innate Immuno

Question 1

What is the role/purpose of the immune system?

Answer 1

1. Protect from pathogens
2. Inflammation
3. Eliminate modified or altered self

Question 2

What are mechanisms of protection?

Answer 2

Mechanical, Cellular, Humoral

Question 3

What are the major differences between innate and adaptive immunity?

Answer 3

Innate- no time lag, not Ag specific, no memory

Adaptive- lag period, Ag specific, development of memory

Question 4

Which cells comprise the innate immune system?

Answer 4

Myeloid cells:
Granulocytic cells, including neutrophila, basophila, eosinophila, and mast cells
Monocytic- macrophages, Kupffer cells (MO in liver), dendritic cells

Question 5

Which humoral components comprise the innate immune sytem?

Answer 5

Complement and interferon

Question 6

What are the other main components of innate defense?

Answer 6

Anatomic barriers, including skin, mucosal membranes (gut and bronchial)
Psychologic barriers, including temperature, fever, basic pH (stomach, skin, vagina), and enzymes

Question 7

What is the purpose of neutrophils/ PMN?

Answer 7

Attack first- phagocytes. Activated by cytokines and respond rapidly to chemotactic stimuli
Express Fc so involved in opsonization for phagocytosis

Question 8

what is the purpose of macrophages?

Answer 8

• Slower than neutrophils but are larger, live longer. -Found in all organs and connective tissues
• Produces cytokines to recruit other inflammatory cells and systemic effects like fever
• APC to Tcell

Question 9

What is Chronic Granulomatous Disease?

What is the treatment?

Answer 9

1. defect in NADPH oxidase system=cannot form ROS….leads to recurrent infections w/ Staph aureus, salmonella, pseudomonas, and fungi
2. education and preventive antibiotics

Question 10

What is the role of NO?

Answer 10

Helps MO in killing intracellular pathogens Vasodilation (drop of bp in sepsis)

Question 11

What is the role of dendritic cells?

Answer 11

sample environment- phagocytize Ag and then migrate to lymph nodes as APC to activate Tcells

Question 12

What is the role of a mast cell?

Answer 12

Bone marrow derived, found in most tissue by blood vessels. Role in inflammation and allergies (with IgE).

Question 13

What is the role of basophils/eosinophils?

Answer 13

Parasitic infections (by using enzymes for tissue damage) and allergies

Question 14

What is the role of interferons?

Answer 14

Stimulate cells to turn on genes for antiviral proteins

Question 15

Why does complement system not attack host cells?

Answer 15

Host cells have proteins that deactivate complement cascade such as DAF and MCP to deactivate C3b and CD59 to deactivate MAC

Question 16

Which cells are involved in adaptive immunity?

Answer 16

Lymphocytes- T cells (Helper, suppressor, cytotoxic), B cells (plasma cells), NK cells

Question 17

What are the key features of an adaptive response?

Answer 17

Specificity, diversity, memory, self-regulation, discrimination of self from non-self

Question 18

What are Antibodies composed of?

How many classes of Ab?

Answer 18

Two light and Two heavy chains, with a constant site and variable site where the Ag binds.
Also, constant region is Fc receptor
5- IgG, IgM, IgA, IgD, and IgE

Question 19

IgG

Answer 19

G: 80% in serum, Neonatal immunity (binds to macrophage and neutrophils via FcR)
viral infections

Question 20

Describe how the binding of Ab inactivates Ag.

Answer 20

Neutrilization, Aggultination, Precipitation, Complement fixation—> enhanced phagocytosis
or cell lysis (MAC)

Question 21

What is the life cycle of a MO?

Answer 21

Made in bone marrow–> monocyte in blood–> tissues MO becomes either (1) activated or (2) microglia, kupffer cell, alveolar MO, or osteoclast

Question 22

The 3 pathways for complement all result in what?

Answer 22

Lectin, classical, and alternative pathways generate C3a–>
C3a and C5a release histamine, chemotactic and increase vascular permeability
C3b opsonin
MAC

Question 23

What is a major difference between B and T cells in terms of Ag recognition?

Answer 23

T cell recognizes small fragment= MHC bound Ag

B cell recognizes larger fragment

Question 24

What is an important feature regarding the type of Ab a single mature B cell is capable of making?

Answer 24

Clonal, which means only 1 type of Ab

Question 25

IgM

Answer 25

M: 13% of serum, First Ab produced, pentameter (can bind up to 5 Ag for opsonization)

Question 26

IgA

Answer 26

A: 6% serum, dimer and secretory component (saliva, tears, colostrum, milk)

Question 27

IgD

Answer 27

D0.2% serum, BcellR, may play role in eliminating self-reactive Ab

Question 28

IgE | Why is second exposure to allergen worse than 1st?

Answer 28

E:0.002% of serum Ab because tightly bound to basophils and mast cells (via Fc region) Parasites and allergic rxns ?: IgE begins binding to mast cell after 1st so by 2nd, its already bound so quicker response

Question 29

How is it possible to generate so many different variable regions of Ab?

Answer 29

Somatic recombination- happens at DNA level before transcription AND different combining of light and heavy chains AND mutation

Question 30

What is ADCC?

Answer 30

Ab dependent cell-mediated cytotoxicity... Ab opsonize virus-infected cell, connect to NK/cytotoxic Tcell--> which release granuoles to kill cell

Question 31

What happens to an immature B cell in the bone marrow if it matches up with Ag?

Answer 31

It would only match with self cells to it would need to be destroyed

Question 32

How does a mature B cell differ from activated B cell and memory B cell?

Answer 32

Mature B cells will die if they don't encounter Ag outside of bone marrow. Activated B cell has matched up with Ag and will proliferate more Ig to be secreted (rather than on membrane)-->plasma cell Memory B cells remain with membrane Ig which may be stimulated to secondary Ab response

Question 33

How does a B cell become activated to produce Ab?

Answer 33

Engulfs Ag--> binds to MHC--> presents combo+CD40 to T cell CD40L--> B cell proliferate to class switch Ig and become plasma cells

Question 34

What is XLA?

Answer 34

Don't generate mature B cells so susceptible to bacterial and some viral infections but not intracellular microbes and fungi (uses NK and MO)

Question 35

What is hyper IgM syndrome?

Answer 35

``` defect in class switch due to CD40L being defective so only have IgM present with persistent bacterial infections and neutropina (and MO deficiency) b/c CD40 important for granulocyte development too ```

Question 36

What is MHC/HLA? What does it have to do with tissue type?

Answer 36

It is the Major Histocompatibility Complex. Co-dominantly expressed and it is part of the way Tcells distinguish self from non-self

Question 37

What are the distinct characteristics of MHC I?

Answer 37

Expressed on all nucleated cells Presents endogenously synthesized Ag (virus in as its passing though ER to be synthesized) Checked by killer T cells (CD8)

Question 38

What are the distinct characteristics of MHC II?

Answer 38

Expressed on B lymphocytes, MO, dendritic cells, and endothelial cells ( may be induced by cytokines though) Presents exogenous Ag proteins (bacterial proteins in vesicles) Checked by Helper T cells (CD$)

Question 39

What role does MHC play in Graft v Host and Host v Graft?

Answer 39

Graft v Host: ex bone marrow= donor immune cells attack host cells Host v Graft: ex kidney transplant= host immune cells attack donated tissue

Question 40

How do the different Ig differ in structure?

Answer 40

Fc receptor region on the heavy chains in response to certain cytokines