1. By physical characteristics of the intestine (intrinsic barrier)
a) Microvillous structure
b) Junctions between cells
2. By resbicting the amount of antigen reaching the surfiace of intestine (cKirinsic barrier)
a) Proteolysis and gastric acidity
b) Peristalsis
c) Mucuscoat
d) Immunologie barrier ✓ Innate
/ Acquired