Microbiology and Immunology 3300B Study Guide - Final Guide: Central Tolerance, Peripheral Tolerance, Afferent Arterioles
DepartmentMicrobiology and Immunology
Course CodeMICROIMM 3300B
Immune Study Notes Lecture 4
Where do immune cells undergo development?
In the bone marrow, but T cells finish in the thymus
1. What are the roles of the central lymphoid tissues?
Antibody/TCR gene rearrangement
2. What happens in the bone marrow?
Hematopoesis, Antibody rearrangement, central tolerence (rendered self reactive or
Bony trabeculae – where immune cells develop, spaces between is where
hematopoeisis occurs and also adipocytes are also present there.
Bell cells go through apoptosis or they undergo change to make them inactive. If
good they stay as receptors.
3. Describe central tolerance in the thymus.
Segmented off by a capsule. Start with the TCR genes rearranging within the cortical
epithelial region, then being selected negatively against within the medulary
epithelial region, no idea what occurs in the Hassels corpus region.
4. Discuss the thymus mutation.
Nude mice – mutation in FOXN1 gene = epithelial cells cant differentiate – no hair,
no thymus therefore prone to infection – also occurs in humans but very rare.
5. What is the function of the peripheral lymphoid tissues?
Peripheral tolerance, maturation of immune cells and antigen screening.
6. What is the function of a lymphnode?
Dendritic cells with antigens will go into he lymphnode through the afferent
arteriole; T/B cells will look for the antigen; if it finds it it will go out and start
immune response; if not; moves onto the next lymphnode
7. Describe the structure and function of the lymph node.
Corticol sinus seperates the components of the lymph node. B cells are found in the
primary lymphoid follicle, T cells are found in the paracortical area. Macrophages
are within the medullary region. Antigens will perculate down the cortical sinus as
the structure changes with immune response. B/T cells will wait and then divide
when active. Germinal centre stores B cells for future attack. T and B cells interact in
the IF zone. T * B cells will have the same antigen and look for each other to start an
What happens in the germinal centres?
Naïve B cells wil take up an antigen – present it as MHC class 2 to t cells.
They will tell it to kill it – antibodies will divide and form a plasma cell making many
antibodies of the same kind.
8. What are HEV?
High endothelial venules that recruit B/T cells ONLY: specialized blood vessels
with Lselectin and ligand
What is the spleen?
Largest lymphoid organ – removes bad RBCs, no immune function but has some
9. Describe the function of the spleen
Blood flows into the PFZ then into the red pulp where RBCs are taken out, then go to
the MZ where macrophages take up antigens then go to the germinal centre to show
T and B cells. Then it returns to the circulatory system.
10. What is included in MALT?
Urogenital tract, lungs and salivary glands.
11. What happens at the mucousal surfaces?
Epithelial cells – immune cells walk around and patrol for pathogens – take up
pathogens (mast cells through phagocytosis and endocytosis) and bring them
through to the other side where the Peyers patch is - contains dendritic cells to
become mature and bring them to the lymphoid vesicles.