Mucosal immunity Flashcards
What is a mucus membrane
Layers of mucosal cells that line body cavities that open to the outside
Produce mucus via mucosal cells
Whata re some of the components of mucosal immunity
Lymphoid elements associated with internal surfaces of the body
Exocrine secretory glands
Factors that protect against GI pathogens
Saliva Stomach acid and enzymes Bile Water and electrolyte secretion Mucosal products Epithelial barrier Peristalsis Bacterial flora
What are the two isoforms of IgA
IgA1 - predominates in serum
IgA2 - higher percentages in secretions
Why is IgA important in mucosal defense
Produced most in mucosal linings
Protects against infectionous agent
Prevents attachment of bacteria or toxins to epithelia
unique features of IgA immunity
Monomeric IgA rpoduced in bone marrow and found in blood
Dimeric IgA produced in lamina propria of mucosal tissues and found in external secretions, Actively transported in external secretions via Pig-R
What are the crypts of lieberkuhn
Intestinal gland
Found in between volli in the intestinal epithelium lining of small and large intestine
What are paneth cells
highly specialised secretory epithelial cells located in the small intestinal crypts of lieberkuhn
Contain dense granules
-antimicrobial peptides, immunomodulationg proteins
-regulate the composition of intestinal flora
What are peyers patches
Organised lymphoid follicles
Help facilitate immune response within mucosa
High presence of B cells
What are M cells
Known to initiate mucosal immunity responses on the apical membrane of the M cells and allow for transport of microbes and particles across the peithelial barrier from the gut lumen to immune cells
What are lamina propria mymphocytes
Found under the epithelium in stroma
Mostly CD4+
-TH1 cells: cell ediated response
-TH2 cells -antibody mediated responses
How are gut responses initiated
M cells are interspersed between enerocytes and in close contact with subepithelial lymphocytes and dendritic cells
M cells take up antigens from the gut lumen by endocytosis
Antigens are released beneath M cells and taken up by antigen- presenting dendritic cells
here does antigen transport occur
Over organised mucosa-associated lymphoid tissue
oral tolerance and how does it break down
Immune responses to food causes intolerance
Immune response to commensal bacteria leads to inflammatory bowel disease
