Theme 1 - cells Flashcards
cells involved in immunity are derived from what?
self renewing STEM CELLS in bone marrow
- differentiate under influence of GROWTH FACTORS into PLURIPOTENT STELL CELLS and then PROGENITOR CELLS
what are the progenitor cells for leukocytes
MYELOID andLYMPHOID (others suspected)
what are the granulocytes
BASOPHILS, EOSINOPHILS, NEUTROPHILS
myeloid progenitor gives rise to what
- erythroid CFU
- megakaryocyte
- basophil CFU
- eosinophil CFU
- granulocyte-monocyte CFU
- pluripotent stem cell
pluripotent stem cell gives rise to
what does that give rise to
lymphoid progenitor which gives rise to:
- NKT cell
- NK cell
- B cell
- T cell
what do erythroid CFU cells give rise to
erythrocytes
what do megakaryocytes give rise to
platelets
what do basophil CFU give rise to
basophils
what do eosinophil CFU cells give rise to
eosinophils
what do granulocyte-monocyte CFU cells give rise to
- neutrophils
- dendritic cells
- monocytes—>macrophages
which growth factors are req for the development of progentor cells
- CYTOKINES (or interleukins-IL)
- COLONY STIMULATING FACTORS (CSF- within bone marrow and later in tissues)
T cells have what on them
CD3
B cells have what on them
CD19, CD21
monocytes have what on them
CD14
what does CD stand for in identifying cells
cluster of differentiation
- the specific molecules they express are used
what do myeloid progenitor cells give rise to
POLYMORPHONUCLEAR LEUKOCYTES/GRANULOCYTES (basophils, neutrophils, eosinophils
in tissues monocytes become what
macrophages
describe neutrophils
- size
- lifespan
- what % of granulocytes are neutrophils
- function
- most important in what
- large (10-20 microns diameter)
- live 2-3 days
- 90% of granulocytes are neutrophils
- neutral staining cytoplasmic granules
- phagocytic, kill bacteria bby MICROBICIDAL mechanisms
- secrete NETs (neutrophil extracellular traps)
- v imp in NON VIRAL inf
- have recepotors for antibody
describe eosinophils
- cont PROMINENT GRANULES wich stain red w/ EOSIN and composed of a crystalline core which is cytotoxic for parasites
- important in immunity to HELMINTH (parasite) inf
- PHAGOCYTIC
- has receptors for IgE antibody
describe basophils
- <0.2% of WBC
- only go into tissues during inflammation
- when stimulated, release substances that promote INFLAMMATION
- important in allergy
- not thought to phagocytose
- have receptors for antibody
describe mast cells
- where did they mature to become mast cells
found where
important where
- immature cells in blood, mature in tissues
- types vary with location and contents of granules
- found in CONNECTIVE and MUCOSAL tissues
- important in ALLERGY: release activating factors eg HISTAMINE and has receptors for IgE (antibody)
what is IgE
Immunoglobin E
antibodies produced by the immune system if allergen present
describe monocytes
MC
- in blood 1-2 days
- mononuclear
- PHAGOCYTIC
describe macrophages
- monocytes mature to macrophages in tissues
- up to 10x larger than MCs
- can live months or years
- characteristics are tissue dep
- PHAGOCYTIC
- adherent
what are the similar characteristics of monocytes and macrophages
- use MICROBICIDAL mechanisms inc ENZYMES
- secrete GFs, chemicals and activation factors
- identified by surface molecules (CD14 and CD15 on monocytes)
- reocgnising foreign materal useing surface receptors, engulf material, and PRESENTING it to other immune cells
- 2 major sub groups
what are the 2 major sub groups of macrophages
M1 AND M2 (more suspected)
what is the macrophage type dependent on
give examples
tissue location
- Kupffer cells in liver
- Mesangial cells in kidneys
- Histocytes in connective tissue
- Osteoclasts in bone
- Alveolar macrophages in lung
- Microglial cells in brain
describe dendritic cells
- irregular shape
- usually myeloid derived
- IMMATURE: capture Ag and migrate to LYMPHOID tissues where they mature and present foreign molecules to T cells
- ANTIGEN PRESENTATION
what are the subtypes of dendritic cells
Langerhans cells (skin)
Interdigitating
plasmacytoid
follicular DCs (usually fibroblasts)
describe megakaryocytes
- if mature = POLYPLOIDY
- remain in bone marrow
- give rise to PLATELETS by CYTOPLASMIC FRAGMENTATION
describe platelets
- anucleated
- contractile
- aherere to other cells and surfaces
- role in blood coagulation
what does a lymphoid progenitor cell give rise to
- B lymphocytes
- T lymphocytes
- NK cells
- NKT cells
- innate lymphoid cells
describe lymphoid progenitor cells size what do they give rise to structure after stimulation
- gives rise to lymphocytes
- 20-30% of PERIPHERAL WBC
- 6-10 microns in diameter
- large nucleus
- small halo of cytoplasm
after STIMULATION by Ag they beocme EFFECTOR or MEMORY cells
- T or B cells
- those that pass to THYMUS mature there and become T cells
- those that stay in BONE MARROW become B cells
describe B cells
- where do they differentiate/mature
- how do they bind foreign molecules
- what do they express as markers
- what do they differentiate into
- what are the subgroups
- remain in bone marrow to differentiate
- taught to not recognise self molecules
- have antibody or immunoglobin molecules anchored to cell membrane forming B CELL RECEPTOR BCR) which binds foreign molecules
- express CD19 and CD21 markers
- when activated differentiate into MEMORY CELLS or PLASMA cells and secrete antibody OR suppressor cells
- subgroups: B1 and B2
describe T cells
- where do they mature
- what do they have on their surface
- what markers do they epxress
- what are the subgroups
- move to thymus to educated to not recognise self molecules and mature
- have T CELL RECEPTOR (alpha and beta strand) on surface to recognise/bind foreign material
- have marker CD3
- 2 main subgroups: CD4+ (helper) and CD8+ (cytotoxic)
describe helper T cells
- express CD4 and CD3
- activated to secrete CYTOKINES in immune respones
- 2 main subgroups: TH1 & TH2
describe cytotoxic T cells
- express CD8 and CD3
- activated to KILL infected targets or to become memory cells
- CYTOTOXIC- kill via release of granule contents (PERFORINS and GRANZYMES) or through induction of apoptosis
describe Regulatory T cells
- express CD4+, some CD8+
- either SUPPRESS or ACTIVATE immune respones via direct cell contact or secretion of soluble factors (cytokines)
- 2 main types: NATURAL or inducible
describe γ/𝛿 T cells
- TCR formed of γ/𝛿 chain
- CD4 and CD8
- recognise lipid antigens
what are the 2 main groups of innate lymphoid cells
NKT cells
- have TCR and kill target cells in a similar way to cytotoxic T cells
- make GFs and signalling molecules
Innate Lymphoid cells
(ILC1, 2, 3) and NK cells
what is the role of innate lymphoid cells and large granular lymphocytes
play role between innate and adaptive immunity
describe innate lymphoid cells and large granular lymphocytes
- 4% of WBC
- larger than lymphocytes, have granular cytoplasm
- kill TUMOURS and VIRALLY INFECTED CELLS and have roles in innate immune respones at SKIN/MUCOSA
describe NK cells
- no TCR but several other receptors to recognise self vs non self
- inc receptors for: GFs, antibody and activatory/inhib receptors
describe innate lymphoid cells
- no TCR
- 3 groups: 1( inc NKs), 2 and 3
- similar properties to TH1, TH2 and regulatory |T cells
- secrete cytokines
- found in skin and mucosa during innate responses
