Immune system
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Transcript Immune system
Immune system
Lecture 2011
Immune system
Innate - non-specific
adaptive – specific
(no immunisation required)
(immunisation required)
o
o
o
o
o
o
physical barriers (skin,
mucosa, cilia)
biological barriers
(symbionts)
chemical barriers (pH,
mucus)
soluble factors (lysozyme,
interferons, proteins ac.ph.,
complement)
Cells: phagocytes,
granulocytes
(rapid answer, restrictive
flexibility, non-specific
reaction, no memory)
Cells: T - lymfocytes
(directly kill cells/ virusinfected, foreign cells,
microorganisms)
o B – lymfocytes
(produce)
o Antibodies
(delayed answer, high
flexibility, high specifity,
memory and immunity)
o
Organs and cells of immune system
Bone marrow
Thymus
Tonsils and adenoids
Lymph nodes
Spleen
Peyer´s patches
Appendix
Lymphatic vessels
Cells of immune system (effect)
non-specific
specific
intracelullar killing macrophages
B-lymphocytes
(mononuclear phagocyte
system)
“activating macrophages“!
produce cytokins
APC!
neutrophils
extracellular killing
NK-cells (CD16, CD56),
“large, granular lymfocytes“
(perforins, apoptosis), not MHC
restricted
eosinophils (granules with
cytotoxic proteins)
(receptor: Ig)
o T-lymphocytes
(receptor:TCR in complex with CD,
Ag split in peptide fragments in
complex with MHC presented
by APC
(Tc) MHC I+Ag
(TH) Ag +MHC II presenting by
APC
Cell origin: Hemocytoblast
(pluripotent stem cell)
Myeloid lineage
Erythrocytes
Plateletes
Granulocytes
Monocytes
Dendritic cells
Mast cells
Lymphoid lineage
B-lymphocytes
T-lymphocytes
NK-cells
Tissues and organs of immune
system
cells: blood, lymph, lymphoid tissue
lymphoid tissue: lymphoid nodules,MALT
primary or central lymphoid organs:
thymus
bone marrow
secondary or peripheral: encapsulated:
lymph nodes
spleen
non-capsulated:
Peyer´s
patches
appendix
tonsils
Cells of immune system
LYMPHOCYTES
Can exist without
contact with another
cells (cytokines!)
Migrate through
tissues, blood and
lymph
2kg in organism/ 23 grams in blood
Lymphocytes
organ
T-lymph %
B-lymph %
thymus
100
0
bone marrow
10
90
spleen
45
55
lymph nodes
60
40
blood
80
20
NK
Cells of immune system
Antigen presenting cells (APC)
heterogenous group of cells
macrophages
dendritic cells
Langerhans´ cells (skin)
B-lymfocytes
M-cells (GIT)
Dendritic cells
APC
originate in bone marrow, progenitor c.
precursors are seeded through the blood to (T-
regions) or to non-lymphoid organs (Langerhans
cc. in the skin)
high ability to be attracted to sites of antigen
challenge and travel via lymph vessels to
peripheral organs, presenting Ag to T-lymph
(satelite lymph node, initiate immune response)
X folicular dendritic cc – origin just in stroma
of nodes, not presenting Ag, but retain Ag/Ab in
membrane – B-lymph and i. memory
Thymus
immature lymphocytes from bone marrow settled the
thymus pre- and postnatally, undergoing -terminal
differentiation and proliferation
elimination 95% (apoptosis), negative selection and
positive selection
cortex (blood-thymus barries) x medulla (postcapillary
venules – mature lymphocytes leave thymus to Tregions in peripheral organs)
reticular epithelial stroma, reticular cells!
Dual embryonic origin - endoderm (3rd pair of
pharyngeal pouches) + mesenchym (lymphocytes),
Intensive growth till puberty
Inborn defect: di George syndrom- thymus aplasia
Thymus
anatomy
Superior and anterior
inferior mediastinum
lobus dx. et sin.
lobuli, cortex, medulla
(lobuli thymici accessorii)
weight at birth (12-14g)
Thymus – cortex (85% T-cells)
epithelial cells – cortical (stromal cells)
secretory granules,desmosomes,3D network,
express MHC I, MHC II
T-cells
double negative, proliferation,gene rearrangement
pre-TCR along with coreceptors CD4 and CD8
double positive (CD4 and CD8), positive selection( CD4 or
CD8)
macrophages negative selection, apoptotic T-cc
dendritic cells
corticomedullary venules (functional thymocytes
exit to circulation to T-regions
Thymus – medulla (25% T-cells)
Fully matured T-cells (single positive)
Epithelial cells
Hassal´s corpuscles (onion –like structures,
degenerated cells
Macrophages
Dendritic cells
NO blood-thymus barrier
Blood – thymus barrier
Cortical epithelial cells
Basal lamina
Basal lamina
Endothelial cells
Macrophages
Only
present in cortex
Thymus involution
Gradual involution from puberty
After 50th year, adipose tissue
Lymph node
organs of lymphoid tissue in the course of
lymphatics
filter of Ag (microorganisms, tumor cells)
coming in the lymph before its return to
blood circulation
recirculation: lymphocytes return to node via
high endothelial venules
reticular connective tissue stroma
cortex (lymphatic nodules, B-lymph)
paracortex (T-lymph)
Lymph node
Cortex:
Subcapsullary sinuses
Lymphatic follicules
Interfollicular sinuses
Paracortex
Medulla
Lymphatic cords
Medullary sinuses
Spleen
largest lymphoid tissue accumulation
filter of Ag (microorganisms, tumor cells) that
penetrate blood, producing antibodies and
activated lymphocytes
White pulp , PALS (T-lymph) + lymhatic
nodule (B-lymph)
Marginal zone (between red and white pulp,
active macrophages)
Red pulp – lymphatic cords of Billroth +
venous sinuses
Vascular supply
Splenic artery
Trabecular artery
Central artery (surrounded by PALS)
Penicilar artery (in red pulp)
Venous sinuses
Trabecular veins
Splenic vein
Spleen – proliferation in germ
center of lymhatic follicle (PCNA)