13: Gut Immunology Flashcards
When do bacteria begin to colonize neonate intestine?
After brith
What does gut microbiota help develop?
Immune system, intestinal homeostasis, metabolism
What can occur with dysbiosis of the gut microbiota
- Growing number of diseases
2. Dysregulation of immune system and inflammation in host
Where are most commensal bacteria in intestinal lumen?
Outside the layers of mucus
ILT stands for?
Isolated lymphoid tissue (follicle)
MAMP
Microbe-associated molecular pattern
What recognizes MAMPs?
PRRs on intestinal ep + DCs next to cryptopatches
What does MAMP recognition cause?
Development of cryptopatches into ILT by recruitment of B and T cells
What occurs with proliferation of intestinal ep during cryptopatch development?
Increased depth and density of Paneth cells in SI
What is present in layer 1 of mucus? Function?
High density of defensins -> largely impervious to bacteria
What can malnutrition cause?
Dysbiosis, defects in innate and adaptive immunity, disruption of barrier function
What can happen with recurrent enteric infections
Predisposed to nutrition deficiencies and impaired barrier function
Immune tolerancer
sustained immune unresponsiveness to self-Ags, beneficial Ags and commensal bacteria
What happens if the body fails to induce tolerance to food?
Food allergy
Describe central tolerance
immature lymphocytes specific for self Ags may encounter these Ags in lymphoid organs and are either 1) deleted 2) change BCR specificity or 3) develop into Tregs
