Exam 2 (Lecture 17) - Body Surface Protection and Mucosal Immunity Flashcards
Describe two to three non-immunologic surface protective mechanisms for maintaining health.
1) Skin
2) Mucous
3) Mucocilliary escalator
Compare and contrast (at least two similarities and two differences) the common mucosal immune system and the systemic immune system.
Common Mucosal Immune System:
- Found in mucosa (not connected to afferent
lymphatics)
- Larger immune system
Systemic Immune System:
- Antigens from lymphatics
- Smaller immune system than mucosal immune
system
Describe what M cells are, where they are found, and what their function is.
Description:
- Dome cells over MALT; transports particles from lumen to lymphoid tissue
Where They are Found:
- In intestinal epithelium, over Peyer’s patches and organized lymphoid tissues of mucosa
Function:
- Take up, sample, and transport particles from lumen of intestines to basal surface of epithelium
Draw and label the basic stick figure for an IgA molecule. List unique characteristics, location in the body, and key functions. (See lectures 6 & 7).
Unique characteristics:
- Dimeric
- Held together by J chain
- Gains secretory component when on mucosal
surfaces
Location in Body:
- Mucosal/luminal surfaces
- Some in plasma
Key Functions:
- Neutralize toxins
- Block entry of pathogens
- Provide intestinal immunity to suckling newborn
Draw or list steps to explain the transfer of IgA from the basal side of the mucosa across the epithelial cells and the release into the lumen, including important receptors and molecules.
Produced by plasma cells on the basal side of the epithelium.
The J chain is IgA binds to PIg receptors on basal surface of epithelium.
Endocytosis (receptor mediated) and transport across cell.
Released into lumen.
Enzymes cleave PIg receptor on mucosal surface.
Retains portion of PIg on IgA = secretory component.
Explain the function of the secretory component and where the IgA acquires it.
Function:
- Transport of IgA across the epithelium
- Protection of the IgA from cleavage by protease
- Binds to mucus so the IgA is not flushed out
Where IgA acquires it:
- During transport across mucosal epithelial cell
- Part of PIg receptor on epithelium
Explain how the sIgA to an intestinal pathogen can be found in the milk of a mare and protects her newborn from the intestinal pathogen (lymphocyte circulation).
Virus enters M cell over Peyer’s patch.
Production of dimeric IgA.
Afferent lymphatics drain into the mesenteric lymph node.
Efferent lymphatics drain into the thoracic duct then into the bloodstream and into the mammary gland.
Secrets into milk with secretory component.
