Lecture 1 - Overview of Immuno

Question 1

What are the 4 classes of pathogens?

Answer 1

1) Bacteria
2) Viruses
3) Fungi
4) Parasites

Question 2

Name 4 features of Innate (Non-Adaptive) Immunity.

Answer 2

1) Rapid Response (hours)
2) Fixed
3) Limited specificity
4) Constant during response

Question 3

Name 4 features of Acquired (Adaptive) Immunity.

Answer 3

1) Slow response (days/weeks)
2) Variable
3) Highly specific
4) Memory allows improvement in response

Question 4

Name the cell from which all elements of blood are derived.

Answer 4

Pluripotent Hematopoietic Stem Cell

Question 5

Chart the differentiation pathway that leads to platelets and erythrocytes.

Answer 5

Hematopoietic stem cell –> Common Erythroid/Megakaryocyte Progenitor –> Megakaryocyte and Erythroblast –> Platelets and Erythrocytes

Question 6

Chart the differentiation pathway that leads to dendritic cells, macrophages, and mast cells.

Answer 6

Hematopoietic Stem Cell –> Common Myeloid Progenitor –> Unknown Precursor –> Mast cell and Monocyte –> (Monocyte only) –> Dendritic cell and Macrophage

Question 7

Chart the differentiation pathway that leads to neutrophils, eosinophils, and basophils.

Answer 7

Hematopoietic Stem Cell –> Common Myeloid Progenitor –> Common Granulocyte Precursor –> Neutrophil, Eosinophil, Basophil

Question 8

Chart the differentiation pathway that leads to B cells, T cells, and NK cells.

Answer 8

Hematopoietic Stem Cell –> Common Lymphoid Progenitor cell –> B cell and NK/T cell precursor –> NK cell and T cell

Question 9

Common Myeloid Progenitor cell makes cells for Innate or Acquired Immunity?

Answer 9

Innate

Question 10

Common Lymphoid Progenitor cell makes cells for Innate or Acquired Immunity?

Answer 10

Acquired

Question 11

Describe the size and function of Megakaryocytes

Answer 11

• 10-15X size of RBC

- make plateles

Question 12

What are PRRs and what does they do?

Answer 12

Pattern Recognition Receptors, and they recognize PAMPs that are expressed by cells of the innate immune system. This is part of the innate immune response.

Question 13

What are PAMPs?

Answer 13

Pathogen-Associated Molecular Patterns, and they are conserved molecular motifs associated with pathogens and are recognized by cells of innate immune system, thus activating the innate immune response.

Question 14

What is the most numerous immune cell in the body, and is responsible for engulfing and killing microbes?

Answer 14

Neutrophil

Question 15

What innate immune cell has receptors that bind to IgE, and destroys parasites

Answer 15

Eosinophil

Question 16

What are the three innate immunity cells produced by the granulocyte precursor, and which is least abundant?

Answer 16

Neutrophils, eosinophils, basophils (least abundant immune cell).

Question 17

Name the three innate immunity cells produced by the unknown precursor that follows the myeloid progenitor cell?

Answer 17

Dendritic cells, macrophages, and mast cells.

Question 18

Which cell ‘steals’ IgE molecules from circulation to use them as Ag-specific receptors? Also, has granules containing histamine.

Answer 18

Mast cell

Question 19

What are the four postulates of the clonal selection hypothesis?

Answer 19

1) Each lymphocyte has a unique receptor
2) Lymphocyte Activation requires binding between foreign molecule to lymphocyte receptor.
3) The differentiated effector cells derived from an activated lymphocyte will bear receptors of IDENTICAL specificity as the parental cell.
4) Lymphocytes bearing receptors for SELF molecules will be DELETED at an early stage

Question 20

What is the most potent Ag-presenting cell of the immune system?

Answer 20

Dendritic cells

Question 21

Monocytes are precursor to what cells?

Answer 21

Macrophages

Question 22

Macrophages and Dendritic cells are INNATE immune cells that help initiate the ACQUIRED immune system by processing and presenting Ag to lymphocytes. T/F

Answer 22

True

Question 23

Macrophages have (blank) and (blank) that allow them to find and destroy opsonized microbes.

Answer 23

complement receptors and Fc receptors

Question 24

Natural Killer (NK) cells are not considered lymphocytes because they have no Ag-specific receptor. T/F

Answer 24

True

Question 25

NK cells have role in both innate and acquired immune responses, doing what two things?

Answer 25

1) kill some virally-infected cells | 2) are effector cells of ADCC (Ab-Dependent Cell-mediated Cytotoxicity)

Question 26

Describes the types of lymphocytes and their roles.

Answer 26

B cells: produce Ag-specific proteins (Ab's) T cells: helper-make signals that direct action of other cells killer- kill cells

Question 27

Name the cells that are fully differentiated B cells, and describe their one role.

Answer 27

Plasma cells are fully differentiated B cells, and their only role is to produce Ab's!

Question 28

What are the two primary (central) lymphoid organs?

Answer 28

Thymus and Bone Marrow

Question 29

T cells are made where and mature where?

Answer 29

Made in bone marrow, mature in thymus.

Question 30

B cells are made where and mature where?

Answer 30

Bone marrow and bone marrow.

Question 31

What are germinal centers?

Answer 31

Germinal centers are B cell follicles in lymph nodes, where B cells are undergoing rapid proliferation, following Ag-stimulation with T cell help.

Question 32

Most of spleen is composed of (blank) pulp.

Answer 32

Red (site of RBC disposal)

Question 33

Lymphocytes surround arterioles that enter the spleen, forming areas called (blank)

Answer 33

White pulp

Question 34

White pulp is subdivided into (blank), which contains T cells, and (blank), which contains B cells.

Answer 34

PALS - periarteriolar lymphoid sheath | B cell corona

Question 35

Tonsils, adenoids, appendix, and Peyer's patches are all types of what?

Answer 35

GALT - Gut associated lymphoid tissues. These capture Ag from epithelial surfaces of the GI tract.

Question 36

What is a unique feature of Peyer's patches?

Answer 36

M cells, microfold cells, which sample Ag from intestinal lumen.

Question 37

In what organs does somatic recombination take place for B and T cells?

Answer 37

Takes place in bone marrow for B cells, thymus for T cells.

Question 38

Somatic recombination is random. T/F

Answer 38

True

Question 39

Which lymphocytes are good for fighting extra-cellular pathogens?

Answer 39

B cells. AB-mediated immune responses are most effective for clearance of pathogens in the extracellular space.

Question 40

Which lymphocytes are good are fighting intra-cellular pathogens?

Answer 40

T cells. T cell-mediated immune responses are most effective for clearance of these pathogens.

Question 41

Define antigen.

Answer 41

Any ligand that binds to B cell or T cell receptors. Most Ag are composed of protein. TCR's bind ONLY to short peptides.

Question 42

Explain the difference of where MHC I and MHC II molecules are found.

Answer 42

MHC I are found on almost ALL host cells. MHC II are found only on immune cells, called APC's. ***MHC's bind to peptides and present them to T cells.***

Question 43

MHC I presents Ag's ONLY to (blank) cells.

Answer 43

CD8 T-killer cells

Question 44

MHC II presents Ag's ONLY to (blank) cells.

Answer 44

CD4 T-helper cells

Question 45

Describe the Ag processing/presenting pathway for MHC I

Answer 45

- Virus infects ANY HOST CELL - Viral proteins synthesized in cytoplasm - Bound peptides transported by MHC I to cell surface - CD8 T-cytotoxic cell recognizes complex of viral peptide and kills infected cell

Question 46

Describe the Ag processing/presenting pathway for MHC II

Answer 46

- Cell-surface BCR of B cell binds bacteria (1st signal of activation); the cell engulfs and degrades them, producing peptides - Bacterial peptides bound by MHC II is in endocytic vesicles - Bound peptides transported by MHC II to cell surface - CD4 T-helper cell recognizes complex of peptide and activates B cell via a cytokine signal (2nd signal of activation)

Question 47

MHC II presents peptide on surface of B cells, and CD4 T-helper cell recognizes peptide. What happens once T-helper has activated B cell?

Answer 47

That B cell proliferates and differentiates into either effector cells (Ab-secreting plasma cells) or memory cells.

Question 48

Describe the two steps of T-cell activation.

Answer 48

T cells specifically recognize Ag peptide being presented by an APC (macrophage, dendritic cell, B cell) and bind to cognate Ag (1st signal). This must be followed by a co-stimulation signal (2nd signal) by the same APC

Question 49

Describe macrophage-mediated initiation of inflammation.

Answer 49

- surface wound introduces bacteria, which activates effector (macrophage?) cells to secrete cytokines. - cytokines cause series of events: vasodilation, increased vascular permeability. Result is mov't of fluid and cells to site. - Infected tissue becomes inflammed, causing PRSH pain,red,swelling,heat

Question 50

What is neutralization?

Answer 50

Ab's can neutralize some pathogen-derived toxins, and even some pathogens themselves.

Question 51

What is opsonization?

Answer 51

Some Ab's can coat Ag, which facilitates uptake of Ag by phagocytes or NK cells.

Question 52

What is complement activation?

Answer 52

Some Ab's can serve as a receptor for the 1st component of the classic complement system. They are said to "fix complement" which facilitates destruction of the Ag

Question 53

Ab's have important role in activation of NK cells for ADCC. T/F?

Answer 53

True

Question 54

Name several functions/roles of Ab's

Answer 54

1) Neuratlization 2) Opsonization 3) Complement Activation 4) Activation of NK cells for ADCC 5) Role in activity of mast cells