Mucosal immunity

Question 1

What is it?

Answer 1

A first line of defence that is an entire organ itself, or another lymphoid organ.

Question 2

Anatomy of immune system

Answer 2

1st line : skin and mucous membranes
-Barrier
2nd line : Innate immunity (natural)
-Non specific
3rd Line : acquired immunity (Adaptive)
-Specfific

Question 3

Epthelium-innate immunity

Answer 3

An epithelial cell barrier

The can secrete chemokines one way.

Question 4

Associated tissues

Answer 4

Lung - BALT
Gut- GALT
Nasal-NALT
Mucosa- MALT

Question 5

Primary and secondary lymphoid organs

Answer 5

Primary : Bone marrow and thymus

Secondary : Spleen, Lymph nodes, MALT

Question 6

Tolerance

Answer 6

Single progenetor cell, give arise to large lymhocytes that has a variety of specific and can bind to any antigen. Body will delete ones which are unreactive, reactive remains against foreign bodies.
Contact with foreign results in activation, differentiation.

Other foreign:
Good, Microbes, Breathing (air particles), Sperm in vagina , Antibodies in breast milk

KEY: Why do our bodies tolerate these foreign bodies?

Need balance protection from bad to good.
Leukocytes arranged along the epithelial cells, as dense follicles of lymphoid tissues or diffusely binded to epithelial cells.

Large number of effector lymphocyte: epithelial cell and lamina propria.

Microvilli contain a lot of leukocytes inside them.

There are special forms of sampling (sampling foreign bodies). M cells take up particles, but other half inside is a big pocket. which surround leukocytes. Foreign bodies endocytose and combine with leukocytes.
Other form is dendridic cells. CD103 is found on the inside, they can go inside the M-cell pockets, but when there are 2 cells lined up(adjacent), they can stick out a finger and sample inbetween the epithelial cells, this is called periscoping/snorkelling.

Bacteria flora:
found on the outside, they are genetically foreign but also unique to out bodies.
10^14 bacterial cells - 1kg
normal development
Metabolism
-Cellulose
-Degrading toxins

Question 7

Antibodies

Answer 7

Produced by B-cells inside, but there is a special way to obtain a different antibody from the inside, which is pushed outside called IGG, the pushing is called transcytosis.
IGA produced > Taken into epithelial cells > exocytosis to gut lumen.

Question 8

Lung

Answer 8

Dendridic cell periscope
Mucociliary mechanism where mucous is expelled
Cough and sneeze

Question 9

Skin

Answer 9

Langerhans cells

Question 10

Psysiological inflammation

Answer 10

Driven by commmensal bacteria
Ensured correct development
Ensured constant sampling by DC