Immunological Functions of the Gut Flashcards
Compare the Innate and Adaptive Immune Systems
Innate Immune System: • Prevent infection and avoids disease • Non-specific • No memory • Mediated by Macrophages, epithelial barrier, secretions
Adaptive Immune System: • Responds to infection and prevents disease • Highly specific • Has memory • Mediated by Lymphocytes, antibodies
What does Systemic Immunity include?
What does Mucosal immunity include?
- Bone marrow, Spleen, Thymus, Lymphatics, Blood circulation
- Eyes, Nose, Mouth, Lungs, Gut, Genitourinary tract
What is the importance of the Mucosal immunity system with microbes?
What are the innate and adaptive immune mechanisms used in this mucosal system?
- Sites normally colonised by microbes - are a main route of entry for infectious microbes
- • Innate mechanisms - mucins, peristalsis, lysozymes
• Adaptive mechanisms - mucosal/secretory immune system
• Discriminates between food and commensal bacteria against pathogens
What are the Lymphoid cells in the gut?
LOOK AT PICTURE!
• Intra-epithelial lymphocytes
• Lymphocytes and macrophages scattered in lamina propria
• Peyer’s patches:
o Very densely concentrated with lymphocytes in ILEUM
o M cells - act as a portal of entry for lymphocytes in the Peyer’s patches
What are the mucosal antibodies produced? Where are they found? What do they provide?
Compare IgG and Secretory IgA
LOOK AT PICTURES!
- Predominantly Secretory IgA - found in all secretions, like breast milk - provides passive immune protection in new-borns
- Both bind to key functional sites on microbes and toxins, and are involved in Agglutination
Only IgG:
• Induce Inflammation
• Recruit immune cells
Only Secretory IgA: • Immune exclusion • Viral excretion • Intra-cellular neutralisation • Interaction with non-specific factors
What are the approaches used in Oral Immunisation?
- Attenuated virus
- Attenuated recombinant bacterial mutants
- Mucosal adjuvants
- Liposomes, Microspheres, Capsules
- Transgenic edible plants
