Lymphoid Organs & Cell Migration Flashcards
1
Q
Where is MALT located?
A
- GIT
- Respiratory tract
- Genitourinary tract
2
Q
Where are mature naive B cells stored?
A
primary follicle
3
Q
Acute Phase Response
A
Increase in the appearance of various proteins in circ. - cytokines and anti-microbial proteins
- IL-1β, IL-6, TNF-𝛼
4
Q
Binding sites of chemokines
A
- to proteoglycans on blood side of blood vessels
- to chemokine receptors on leukocytes
5
Q
chemokinesis
A
non-directional movement
6
Q
Chemotaxis
A
- directional migration of cells up a conc. gradient of chemotactic molecules
7
Q
Components of Inflammatory Response
A
- blood supply increases
- capillary permeability increases - allows exudation of serum proteins in surrounding tissue - abs, complement
- leukocyte migration to site:
- NFs first
- APCs
- CTLs and TH - need to be activated first by APCs in lymph nodes/spleen
- B lymphocytes
8
Q
Composition of IL-2R
A
alpha (low affinity alone)
beta
gamma chains
*highest affinity occurs when all 3 form a receptor triggering activation of immune cells
9
Q
Cytokines
A
- secreted glycoproteins
- produced mainly by T-helper cells and APCs (dendritics, Macs)
- pleiotrophic - many functions
- redundant - some can mediate a similar function (IL1 and IL6)
- interact with high affinity receptors
- only produced when immune system is activated
e.g. IL2 produced by activated Th cell which binds to IL2r (CD25)
10
Q
Cytokines involved in myeloid cell development
A
- CFU-GEMM (give rise to all granulocytes and monocytes)
- IL-3
- GM-CSF (granulocyte, monocyte, colony stimulating factor)
- G-CSF (granulocyte)
- M-CSF (monocyte)
- EPO (erythropoietin)
11
Q
Describe the development of the immune system
A
- derived from totiopotent haemopoietic stem cell (HSC)
- differentate based on:
- cell to cell contact
- presence of cytokines
- HSCs are found in bone marrow and spleen (in mammals)
12
Q
Example of chemokine
A
IL-8 (CXCL7)
- produced by macrophages
- attracts NFs to site
13
Q
Example of Recombinant GM-CSF and G-CSF GFs
A
- Leucomax - Novartis
- Neulasta (Amgen)
- application in chemotherapy
- targets rapidly dividing cells in bone marrow - neutropenia occurs (deficiency in NFs) - drugs prevent this from occuring
14
Q
Examples of diseases associated with chronic inflammation
A
- pul diseases
- cancer
- CVD
- Alzheimers
- Diabetes
- Arthritis
- Autoimmune diseases
- Neuro disease
15
Q
Examples of duality in the immune system
A
- innate & adaptive
- innate - phagocytes & APCs
- adaptive - B cells & T cells
- T cells - Th & CTC
- B cells BCR - Heavy & Light chains
- T cells TCR - alphabeta TCR & gammadelta TCR
- recognition of self and non self
16
Q
Function of spleen
A
- monitors blood-borne infections
- white pulp - contains T and B cells
- red pulp - removal of aging RBCs and platelets - phagocytosed by macrophages
17
Q
Where are immune cells from the circulation homed?
A
high endothelial venue (HEV)
18
Q
IL2 & IL2r
A
- production of IL2 and its interaction with IL2R - crucial for immune system activation to infection
19
Q
Leukocyte migration across endothelium
A
- vasodilation of vasculature is vital - slows flow down and decreases prosthetic repulsion
- vasodilatory molecules
- bradykinin
- PGs
- Histamine
- Leukotrienes
20
Q
Lymph journey
A
Arrives via several afferent lymphatic vessels
Leaves via one efferent lymphatic vessel
21
Q
Name chemotactic molecules
A
- C5a - complement protein (chemoattractant for NFs and macrophages)
- f-met-leu-phe - bacterial tripeptide (chemoattractant for NFs)
- chemokines - small cytokines
22
Q
Opsonins
A
- induce phagocytosis
- C-reactive protein
- serum amyloid protein
- mannose-binding protein
23
Q
Primary Lymphid Organs
A
- haemopoietic stem cell
- bone marrow - stem cells give rise to all immune cells except T cells
- thymus - produces T cells
24
Q
Production of B cells in bone marrow
A
- Immature cells stimulated to recombine their H and L chain genes - produces functional BCR
- many B cells never reach circulation - fail to make a BCR - death by neglect
25
Secondary Lymphoid Organs
\*home to most non-circulating immune cells
* lymph nodes
* spleen
* GALT/ BALT
26
Site of self/non-self T cell education
* outer cortex - immature proliferating thymocytes
* inner medulla - mature thymocytes
27
Sites of leukopoiesis
* bone marrow
* thymus
- leukocytes differentiate from myeloid and lymphoid progenitor stem cells
- proliferate
- mature into functional cells
28
Symptoms of inflammation
1. redness - rubor
2. heat - calor
3. pain - dolar
4. swelling - tumor
5. altered function
29
Types of Cell Migration that take place
* to sites of infection and inflamm
* from blood to lymph and vice versa
* from primary to secondary lymphoid organs
* between secondary lymphoid organs
30
Types of Th cells
1. **Th1 - IL2, TNF alpha**
2. **Th2 - IL4,5,13**
3. Th17 - IL17,22
4. Tfh - IL 21
31
What cells undergo hemopoiesis in bone marrow?
all immune cells except T cells
32
Which pathways deliver signal transduction from IL-2R to the nucleus ?
* Ras-MAPK
* PI3K-Akt
33
𝛼CXC vs βCC
* alpha chemokines or CXC - chemotaxis or cell migration
* beta chemokines or CC - cell activation
34
Leukocyte recruitment to tissues
* at site of infection, macrophage activate nearby endothelial cells of venules to produce integrins, selectins, ligands, chemokines
* selectin - mediate weak tethering of blood leukocytes on endothelium
* force of blood flow causes leukocytes to roll across endothelial surface
* integrins activated to high affinity state by chemokines
* activated integrins bind Ig ligands to endo cells causing firm adhesion
* leukocytes crawl into junctions between end cells and migrate to venular wall
35
CRP production
* increases 1000x due to IL-6, IL-1
* in severe COVID patients - increased IL-6 and CRP levels
