5/14/2019 1 Defence on Body Surfaces Veterinary Immunology Veterinary education, 3 rd year 31/03/2019 Defence on the Mucosa Defence on the Mucous Membranes Physical defences • Skin, mucous membranes, hair/feather, mucous • Movements: palpebra reflex, peristalsis, retroperistalsis • Flushing: saliva, tear, urine, sweating Chemical barrier • Unfavorable pH for microorganisms • Antimicrobial materials Biologicalbarrier • Microbiome Defence of cells • Tight junctions between epithelial cells • Ciliary movement in the upper respiratory tract Entry of the Pathogens https://viralzone.expasy.org
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Defence on the Mucosa Defence on Body Surfaces• Movements: palpebra reflex, peristalsis, retroperistalsis • Flushing: saliva, tear, urine, sweating Chemical barrier • Unfavorable
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Defence on Body Surfaces
Veterinary ImmunologyVeterinary education, 3rd year
• 200-300 m2 surface in an adult• Tonsils, appendix, Peyer's plaques, folliculi• 2/3 of immunoglobulin production of the body
and more lymphocytes as in all other parts of the body
Main task: local immune response• Complete exclusion of various infectious agents
and other antigens in the intestinal lumen• Induction of tolerance
GALT
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GALT
Effector site Inductive siteOrganized lymphoid tissue
Laminapropria
M cell: microfolded cell (Atg transport from the lumen)SED: subepithelial dome (DC: atg transport to the zone
of T-cells)TDA: T-dependent territoryIEL: intraepithelial lymphocyte
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Lymphocytas arrived through HEV. Receptors CCR7 and L-selectin are attractedto kemokines CCR19 and CCR21 wich selected by secunder lymphoid tissues(not just Peyer’s patches).
Naive Cells
Lymphocytasrecirculatethrought HEV
(HEV)
M-Cell
CCL19 és CCL20
Activation of DC-cell–T-cell–B-cell
• Activated lymphocytas homing– Lymphocytes express homing receptors because
of retinol acid produced by DC
– Homing receptors will direct lymphocytes to the lamina propria
– OR the activated lymphocytes leave the Peyer’s patches throught lymphatic ducts to a mesenteric lymph node
• DC presenting an Atg migrates to lymp nodes to activate naive T-cells
Homing of T-cells, B-cells
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Activation of Lymphocytesin a Lymp Node
• B-cell mature to plasma cell in lymp node
• Activated cytotoxic and helper T-cells and IgMproducing B-cells leave the lymp node through the efferent lymphatic duct
• IgM producing plasma cell has class switching to IgA producing plasma cell that is helped by IL5 and IL6 produced by Th-cell
Homing
Lamina Propria
Laminapropria
Epithel cells
CD8+ T-cells
CD4+ T-cells, lotsmemorycell
• Cells migrate from efferent lymphatic ducts to the lamina propria through an artery
• Chemokins and adhesion receptors help this migration from blood vessels to the lamina propria
• Matured cells activate in lamina propria
Cytotoxic T-cell
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Phagocytosis of DC
By opsonisation of IgA Between cells By apoptosis caused by CD8+ cells
DC-cell
DCs rarely reach out to epithelial cells because of the tight junctions
• DC presents antigens also on MHCII!
• Activated DC migrates to a mesenteric lymp node through the efferent lymph duct, than activate naive cells…
• Neutrophil granulocytes also have phagocytotic activation
• IL-10 produced by DC stops the activation of cytotoxic cells