Cellular and Molecular Tools Needed for Host Defenses

Question 1

Where do immune system cells come from?

Answer 1

All cells of the immune system are descendants of a pluripotent hematopoietic stem cell found in the bone marrow  two lineages.

Question 2

What regulates the repertoire of cells produced during Hematopoiesis?

Answer 2

Growth factors and cytokines

Question 3

Two important subdivisions of Hematopoiesis are what?

Answer 3

Common Lymphoid Progenitors and Common Myeloid Progenitors.

Question 4

_______ markers are used to help identify different cell types.

Answer 4

Phenotypic

Question 5

The pluripotent hematopoietic stem cell expresses _____.
True or false, all descendent express CD45, but not CD34.
Do erythrocytes express CD45?

Answer 5

Pluripotent hematopoietic stem cells express CD34.
True
No

Question 6

Myeloid cells include what types of cells:

Answer 6

Neutrophils, Eosinophils, Basophils, Monocytes and Dendritic Cells.

Question 7

_______ transform into macrophage upon entry to tissues. _______ are assume to be populated into tissues by blood borne precursor cells produced in the Bone Marrow.

Answer 7

Monocytes.

Mast cells

Question 8

Lymphoid cells include what:

Answer 8

B-cells, T-cells, NKT cells and NK cells.

Question 9

______ are terminally differentiated B-cells.

Answer 9

Plasma cells

Question 10

B-cells express _______ as the antigen receptor and secrete homologous as antibody. True or false, plasma cells don’t express surface immunoglobulin, but secrete large amounts of antibody.

Answer 10

immunoglobulin as the receptor
immunoglobulins as antibody
True

Question 11

______ and _____ express T-cell receptors. ____ cells do not express an antigen receptor.

Answer 11

NKT and T cells

NK

Question 12

Whole blood can be separated into different components based on density. ____ and _____are the most dense and quick sediment during centrifugation. _____ have an intermediate density, while ____ cells are at the top upon centrifugation.

Answer 12

Neutrophils and erythrocytes - most dense
Lymphocytes - intermediate
Plasma

Question 13

______ release material as they are translated. ______ is immediately transported through golgi and released.
______, on the other hand, collect things and are released from vesicles in triggered fashion. Classic example is mast cells

Answer 13

Lymphocytes. Cytokine.

Leukocytes

Question 14

Cells derived from hematopoiesis come from what two places?

Answer 14

1) in utero the stem cells originate from fetal liver

2) bone marrow

Question 15

Myelocytes are derived from where?

Answer 15

Stem cells located in bone marrow

Development occurs in the bone marrow

Question 16

Lymphocytes fall into two categories and come from what?

Answer 16

Lymphocytes come from stem cells located in bone marrow.
*B cell development occurs in the bone marrow
Life long
*T cell development occurs in the thymus
Newborn through puberty

Question 17

How do macrophages kill target cells?

Answer 17

DON’T kill bacteria by phagocytosis. Kill by using puncturing target cells and then injecting ROS and digest from there. Dendritic cells do more antigen presentation than macrophages.

Question 18

The following are types of what cell?
Liver   		Kupffer cell
Bone		Osteoclast (not immune fnxn)
Soft tissue	Histiocyte 
Plaque		Foam cell (cholesterol)
CNS			Microglia
Granuloma	Multinucleated giant cell

Answer 18

Macrophages

Question 19

Mast cells: description and location

Answer 19

Large (10-15 um), irregular shaped
Large granules (histamine, heparin, TNF alpha)
Tissues
Skin
Lung alveoli
GI mucosa
Nasal mucosa

Question 20

Products of mast cells upon injury, antibody or complement:

Answer 20

histimine and leukocytic chemotactic factors

Question 21

Products of mast cell synthesis:

Answer 21

prostaglandins, thromboxanes & leukotrienes

Question 22

_____ are FIRST RESPONDERS to sights of inlammation. The are the most common of all _____.

Answer 22

Neutrophils, leukocytes.

Question 23

True or false, neutrophils have a short half life, are constantly generated and are readily available in circulation for when called upon.

Answer 23

False, while they do have a short half life and are “ready to go”, neutrophils are bound to vessel membranes until called upon.

Question 24

Cortisol and epinephrine (due to stress) stimulate release of neutrophils in a process called ______. How do these cells kill their targets?

Answer 24

demarginalization. R.O.S. injection/phagotysosis

Question 25

Neutrophil overview:

Answer 25

50-70% of leukocytes
60% of bone marrow activity, short life at 12 hrs
Fc and Complement Receptors
Phagocytosis
Lytic secretions (Lysozyme, oxidases and defensins)
Bands
Pus

Question 26

_____ attach to antibody-coated parasites and try to make hostile environment for parasites so they move on.

Answer 26

Eosinophils

Question 27

Eosinophil overview:

Answer 27

Allergies and helminthic parasites
Large and low abundance
Peroxidase, basic proteins, leukotrienes
Generally in bone marrow and connective tissue
Fc-ε
Phagocytosis
Attaches to target for extracellular degranulation

Question 28

_____ are now considered regulators of inlammatory process. These cells appear to take resident in lymph nodes where allergens or parasitic infections are. This causes them to release their compounds.

Answer 28

Basophils

Question 29

Basophil overview:

Answer 29

Smallest (5-7 um)
Lowest abundance (>1% of leukocytes)
Fc-ε
Histamine
Short lived (days)

Question 30

These cells are responsible for killing cells that do not express MHC class I. They do/do not have antigen receptors. Screen cells for what they are hiding.

Answer 30

Natural Killer (NK)
Do NOT have antigen receptors
Work in tandem with T killer(cytotoxic) cells as both induce apoptosis.

Question 31

Natural Killer (NK) overview:

Answer 31

A part of innate immune response
Lymphoid derived
No antigen receptor
Screen for the absence of MHC class I
Induces apoptosis in target cells by releasing lytic granules

Question 32

_____ are the principal cells responsible for stimulating naïve T cells.

Answer 32

Leukocytes.

Question 33

Leukocyte overview:

Answer 33

Process Ag for MHC class II display
Identifies Non-self using receptors for PAMPs
Myeloid derived (mDC)
Leukocyte derived (pDC, plasmacytoid)
DC, Langerhand’s cell, Histiocyte

Question 34

Positive selection happens at level of _____cell.

Answer 34

dendritic

Question 35

Cell found only in the circulation (at all times)

a) Neutrophil
b) Macrophage
c) Lymphocyte
d) Dendritic cell
e) Monocyte

Answer 35

Monocyte

Question 36

Cells communicate through ______. True/false, these cells are readily available. True/false, release of these gives us energy.

Answer 36

Cytokines. False, synthesized on demand. False, release of these makes us feel sick.

Question 37

Cytokine overview:

Answer 37

Direct cellular differentiation
Soluble mediator
Synthesized on demand
Small glycoprotein
Autocrine
Paracrine
No discrete organ, ubiquitously found
Originally coined to emphasis immune function
Commonly operate in sequential patterns, cascading

Question 38

Growth factors and secondary factors associated with Cytokine direction of cellular differentiation:

Answer 38

Growth factors (e.g. GM-CSF, G-CSF) stimulate hematopoietic activity. Secondary factors help to refine the development process (e.g. IL-3, IL4, IL5, IL6).

Question 39

Active Immunization causes antigen to be expressed by
MHC class I
MHC class II
CD1
Antibody
Selectins

Answer 39

MHC Class 1
...Class II can present live or dead. To give long-lasting robust immune response, live (MHC class 1) is preferred.

Question 40

Recognition of non-self

Answer 40

Dendritic cell picks up antigen in inflammatory site. Activated by PAMP… presents w/ MHC molecule. T cell recognizes it as non-self. Dendritic cell determines what type of T cell results to perform certain action…gives T its purpose.

Question 41

Aspects of non-self recognition

Answer 41

Proteins and peptides are scavenged by myeloid dendritic cells
Proteins are processed to small peptides for display to T cells
Antigen display
T cells express surface receptors that weakly recognize peptides
Peptides must be displayed for detection
T cells screen mDCs for Ag
A match results in T cell activation

Question 42

Antigen presentation:

Answer 42

Peptide fragments (8-15 amino acids) are tethered to a protein platform

Provides access to other cells to sample the displayed peptide

Question 43

In antigen presentation, which cells express MHC Class II? Is this display self or extracellular proteins?

Answer 43

Dendritic cells, Macrophage and B cells express MHC Class II

Antigen display is of extracellular proteins

Question 44

Which cells present MHC Class 1? is this display extracellular or self proteins?

Answer 44

All cells (except RBC) express MHC Class I

Antigen display is of self-proteins

Question 45

T Cell receptor recognizes what in antigen-presenting cell?

Answer 45

Antibody recognizes only surface epitopes.
TCR recognizes peptide displayed by MHC
Epitope could be sequences interior in native protein
Epitope is defined by several (2-4) contacts with amino acids

Question 46

Antigen Recognition

Answer 46

Immunoglobulin
B cells use cell surface immunoglobulin
T cells use a fragment of the immunoglobulin at the cell surface

Question 47

How are lymphocytes activated?

Answer 47

Dendritic cells (DC) activate naïve T cells (To) in the lymph node . Depending on the type of PAMP to activate the DC will in turn control how the DC will activate the To. In the lymph node the To will screen MHC class II antigens to find a match. A matched To to the DC is then activated. The To develops into a Th1, Th2 or Th17 cell based on the PAMP.