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Questions and Answers
Which of the following statements about oral tolerance is true?
Which of the following statements about oral tolerance is true?
What is a characteristic of oral tolerance?
What is a characteristic of oral tolerance?
Which of the following statements about oral tolerance is false?
Which of the following statements about oral tolerance is false?
What is a general property of oral tolerance?
What is a general property of oral tolerance?
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Which of the following statements about oral tolerance is true?
Which of the following statements about oral tolerance is true?
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What is a characteristic of oral tolerance?
What is a characteristic of oral tolerance?
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Which of the following statements about oral tolerance is false?
Which of the following statements about oral tolerance is false?
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What is a general property of oral tolerance?
What is a general property of oral tolerance?
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Which of the following statements about oral tolerance is true?
Which of the following statements about oral tolerance is true?
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What is a characteristic of oral tolerance?
What is a characteristic of oral tolerance?
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Study Notes
Mucosal Immunity
- The adult gut processes over 1 ton of nutrients per year, with a large surface area specialized for absorption, spanning around 400m².
Systemic vs. Mucosal Immunity
- Mucosal tissues encounter undefined antigens continuously, whereas systemic environments encounter them rarely.
- Mucosal immunity is essential for protection against pathogens, preventing hypersensitivity to foods and commensal organisms, and for vaccine development.
Mucosal Tissues and Cells
- Mucosal associated lymphoid tissue (MALT) includes inductive and effector sites, such as NALT (Nasal), GALT (gut), and others.
- Peyer's patches contain 50% B cells, 30% T cells, and 8% macrophages, with few plasma cells.
- Isolated lymphoid follicles (ILFs) are induced by commensal gut microorganisms and contain mainly B cells, some T cells, and dendritic cells.
Peyer's Patches and ILFs
- Peyer's patches are inductive sites of GALT, connecting to the lymphatic system only by efferent lymph vessels.
- B lymphocytes from Peyer's patches give rise to IgA-producing plasma cells that home to all mucosal sites.
M Cells
- M cells are specialized epithelial cells that take up and transport particulate antigens, located above Peyer's patches and ILFs.
- M cells are targets for particles, viruses, parasites, and bacteria, including cholera toxin, poliovirus, HIV, and more.
Cells of Mucosal Immune System
- Conventional cells include dendritic cells, macrophages, neutrophils, mast cells, eosinophils, and basophils.
- Specific cells include epithelial cells, M cells, intraepithelial lymphocytes (IELs), and lamina propria T cells.
Lamina Propria T Cells
- Lamina propria T cells are mainly CD4+, produce cytokines, and express α4β7 integrin.
- T cell subsets include Tregs, Th1, Th2, and Th17, each with distinct functions and cytokine production.
Intraepithelial Lymphocytes (IELs)
- IELs are mainly CD8+, express αEβ7 integrin, and are unresponsive to TCR stimulation.
- IELs can be derived extrathymically and recognize MadCAM and CCL25, homing to mucosal tissue.
Lymphocyte Homing
- Homing involves chemokines, rolling adhesion, and tight adhesion, facilitated by α4β7 integrin and MAdCAM-1.
- Further migration occurs through chemokine recognition, such as CCL25 and CCL20, and adhesion through E-cadherin.
B Cell Function: Secretory IgA
- Secretory IgA is produced by mucosal B cells and is essential for mucosal immunity.
- IgA production is influenced by TGFβ and IL-5 and has different functions and activities compared to IgG.
Oral Tolerance
- Oral tolerance requires a functional immune system and symbiosis with commensal organisms.
- Features of oral tolerance include antigen specificity, partiality, and a quantitative reduction in antibody levels, which wane with time.
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Description
Test your knowledge on mucosal immunity and immunology with this quiz covering topics such as mucosal surfaces, lymphocyte homing, B and T cell functions, and oral tolerance. Explore the differences between systemic and mucosal immunity and the specialized cells involved in mucosal immunity.
