Term
| What are the stages of a DTH reaction? |
|
Definition
DTH occurs days following exposures and involves CD4+ and CD8+ T cells
1) SENSITIZATION- T helper cells are activated and clonally expanded by antigen presented on MHC-II (1-2 weeks)
2) EFFECTOR- Subsequent exposure initiates Th1-release of IFN-y and Th-17 release of IL-17 that act on vascular endothelium and recruit macrophages (24h after 2nd exposure, peaking at 48-72h)
3) can become CHRONIC if antigen is not cleared |
|
|
Term
| What is "Contact Dermatitis" and how does it arise? |
|
Definition
Formaldehyde, turpentine, cosmetics, poison ivy, ect.
Small molecules complex with skin and are internalized by APCs (Langerhans), processed and presented with class II MHC leading to sensitization of Th1 |
|
|
Term
| How do caseating granulomas arise in TB infection? |
|
Definition
Aggregation of epithelioid macrophages that fuse to form a Langhan's giant cell.
The central portion of the granuloma is surrounded by Th1 cells.
Damage to tissue is due to mass affect of granuloma and NOT release of mediators that damage cells.
Same granulomas are seen in fungal infections. |
|
|
Term
True or False
Organ damage in TB is caused by cytokine mediators released by Th1 cells that surround caseating granulomas. |
|
Definition
False
The damage is caused by the mass affect of granulomas on anatomy. |
|
|
Term
| Describe the defining features of MS. |
|
Definition
1) Inflammatory disease of CNS (white matter)
2) Plaques or lesions appear in random areas of CNS that present with demyelination.
3) TH1 and TH-17 subsets of T cells are involved in DTH response in CNS and may cause demyelination. |
|
|
