BIOL 435 Ch. 2 Part One (Cells and Organs of the Immune System) Flashcards
1
Q
immune responses rely on
A
-the development of specialized blood cells (WBCs/leukocytes (ex. lymphocytes))
>only the first step
2
Q
immune responses result from
A
- coordinated activities of many cells, organs and microenvironments in the body
- cells must interface with each other to trigger immune responses
- interfaces and tissues involved are complex
3
Q
hematopoietic stem cells (HSCs)
A
-have the ability to differentiate into many types of blood cells
4
Q
all RBC and WBC develop
A
-from multipotent HSC during hematopoiesis
5
Q
totipotent
A
-can become any part of the embryo or placenta
6
Q
multipotent
A
-differentiate into many cells but NOT into every type of cell
7
Q
hematopoiesis
A
- a highly regulated process
- in adult vertebrates it occurs in bone marrow
- early on it occurs in various places as development proceeds
8
Q
within bone marrow
A
-HSCs are constantly renewed and directed to differentiate into 2 major types of progenitor cells
9
Q
2 major types of progenitor cells
A
- Common myeloid progenitor cells
2. Common lymphoid progenitor cells
10
Q
4 cells that develop from common myeloid progenitors
A
- RBCs (erythrocytes): 99.85%
- Monocytes
- Granulocytes
- Megakaryocytes
11
Q
subtypes of granulocytes
A
- neutrophils
- basophils/mast cells
- eosinphils
- differ in granule staining and in protein content and function
12
Q
neutrophils
A
- 50-70% of leukocytes
- phagocytic cells that differentiate in bone marrow
- circulate in peripheral blood for 7-10hrs, then migrate into tissues (not all released at the same time)
- life span in tissue: only a few days
- may secrete cytokines that regulate T- and B-cell activity
- engulf bacteria and release proteins
13
Q
molecules in granules of neutrophils
A
- proteases
- antimicrobial proteins
- protease inhibitors
- histamine
14
Q
proteases
A
- tissue remodelling
ex. elastase, collagenase
15
Q
antimicrobial proteins
A
- direct harm to pathogens
ex. defensives, lysozyme
16
Q
protease inhibitors
A
- regulation of proteases
ex. alpha1-antitrypsin
17
Q
histamine
A
- vasodilation
- inflammation
18
Q
eosinphil
A
- 1-3% leukocytes
- phagocytic granulocytes stain pink with H+E
- coordinate our defences against multicellular parasitic organisms (worms)
- cluster around worms and release granules
- motile, migrate from blood into tissues
- most abundant in small intestines
- if no worms, may contribute to allergies + asthma
- may secrete cytokines that regulate T- and B- cell activity
19
Q
molecules in granules of eosinophil
A
- cationic proteins
- ribonucleases
- cytokines
- chemokines
20
Q
cationic proteins
A
- induces formation of ROS (ex. EPO)
- vasodilation, basophils degranulation (ex. MBP)
21
Q
ribonucleases
A
- antiviral actiivty
ex. ECP, EDN
22
Q
cytokines
A
- modulation of adaptive immune responses
ex. IL-4, IL-10, IL-13, TNF-alpha
23
Q
chemokines
A
- attract leukocytes
- RANTES, MIP-1alpha
24
Q
basophils
A
- less than 1% leukocytes
- nonphagocytic granulocytes containing large basophilic granules (stained blue in H+E)
- involved in response to parasites (parasitic worms)
- bind circulating Ag/Ab complexes then release granules
- histamine increases blood vessel permeability and smooth muscle activity (can be involved in allergies)
- allows immune cells to access the site of infection
- release cytokines that recruit other immune cells including eosinphils and lymphocytes
25
molecules in granules in basophils/mast cells
- cytokines
- lipid mediators
- histamine
26
lipid mediators
- regulation of inflammation
| ex. leukotrienes
27
mast cells
- less than 1% of leukocytes
- non-phagocytic granulocytes involved in response to parasitic worms (contributes to allergies)
- released from bone marrow as undifferentiated cells
- mature only after they leave the blood into tissues
- large numbers of granules
- 1st immune response to allergies
28
pAPC
- professional antigen presenting cells
- monocytes/macrophages and dendritic cells (myeloid lineage)
- secrete proteins that attract and activate other immune cells
- internalized pathogens, digest them into proteins and present them on cell surface in MHC class II
- up-regulate costimulatory molecules required for optimal activation of helper T-cells
* important between innate and adaptive immunity
29
monocytes
-2-12% of leukocytes
-migrate into tissues and differentiate into macrophages
>function to repair, destroy pathogens + present antigens
-can also differentiate into dendritic cells
>HIGH degree of function as 'ingestors' of antigens followed by presentation to naive T lymphocytes for initial activation
30
macrophage
- along with neutrophils are specialized for phagocytosis
- can present antigens to T cells via MHC (=pAPC)
- first to fight pathogens
- some arise from embryonic cells as tissue-specific (resident)
31
tissue-specific(resident) macrophages
- used to think they all came from monocytes
- some arose earlier and are maintained
- specific jobs dependent on cell type
32
dendritic cells
- the most potent APC for activating naive T-cells
- immature ones capture antigen, then mature and migrate out of that location to another to present antigen to T-cells
- can be formed through myeloid progenitor cell or monocytes (both innate and adaptive immunity)
33
megakaryocyte
- large myeloid cells (reside in bone marrow)
- give rise to 1000s of platelets
- have properties of individual cells, but do not have their own nuclei
34
platelets
- small cells or cell fragments
| - circulate in the blood and participate in the formation of blood clots
35
life spans
- RBC: 120 days (recycled)
| - platelets: 5-10 days
36
H + E stains
- hematoxylin (binds to negatively charged stuff (ex. DNA) = purple
- eosin (cytoplasm and other stuff = pink)
37
neutrophil extracellular traps (NETs)
-'eject' DNA and create a net to capture bacteria (sacrifice)
38
simple pAPC
- present antigen to T-cells
1. Phagocytosis (big)
2. Receptor mediated endocytosis
3. Pinocytosis (small stuff)
* bring in and cut into Ag (peptides)
39
IgE
-comes from B-cells
>allergen=antigen
-binds to mast cell IgE receptor
40
APC
-B-cells
| >not professionals
41
MHC classes
1. MHC 1: all cells
- altered self (ex. virus, cancer)
- activated by cytotoxic T-lymphocyte (CTL)
2. MHC 2: APC
- activate T-helper cells
42
APC and MHC
1. Fragment of protein inside cell associates with MHC and is transported to the cell surface
2. Combo of MHC and antigen is recognized by a T cell, altering it to the infection
43
3 common lymphoid progenitor cells
1. B lymphocytes
2. T lymphocytes: subset that appears more simlar to NK cells=NTK cells
3. Innate lymphoid cells, including NK cells
* 20-40% of circulating WBCs
- 99% of cells in lymph
44
lymphocytes
-appear very simlar, but different sets carry different molecules on their surface
>cluster of differenitiation (CD) molecules
45
B-cells, T-cells and NK cells
- express many different CD proteins
- B-cells also express the BCR
- T-cells also express teh TCR
- memory cells from B and T-cells
46
T helper vs. T cytotoxic cells
-undergo gene rearrangement
>CD4: T helper cell
>CD8: T cytotoxic cell
-could have same TCR
47
BCR
-essentially antibodies on cell surface
-antigen can bind to 1 or 2 arms ('different' receptor)
>increase signal to inside
-2 heavy chains and 2 light chains
48
TCR
-2 chains
-bind to peptide held out by MHC
>MHC II: T-helper cell (CD4 must also see MHC II)
>MHC I: T-cytotoxic cell (CD8 must see MHC I)
