Quiz3 Flashcards
What kind of pathogen stimulates macrophage killing? And what MHC receptor/cell mediator?
Intravesicular pathogens; MHC 2, cd4+ cells
What kind of pathogens lead to cytotoxic killing?
Cytosolic pathogens
What kind of pathogen stimulates B cell activation?
Extracellular
What are conventional migratory APCs?
APCs that start in periphery and migrate to nearest LN; include
What is a plasma you’d APC?
Lives in blood, LN, thymus
Where are proteins presented on MHC 1 from?
Cytosolic pathogens, processed by proteosome, introduced to ER by TAP proteins, loaded onto MHC1 by tapasin, complex held by calreticulin, before exocytosis and getting displayed
How long are the segments produced by proteosome degradation?
6-24 AAs long
How do type 1 IFN’s affect immunoproteosomes?
Increase thru-put, alter specificity, enhance Ag presentation, make smaller antigens; essentially pushes expression towards MHC1 expression for viral/cytotoxic response
Describe the loading of Ag protein for class 1.
Proteosome degrades, TAP brings into ER, calnexin holds MHC to complex with b2m, calreticulin moves complex towards protein, tapasin stabilizes complex, and Erp57 loads
Which MHC class is stabile without any protein bound?
Class 2, class 1 degrades and is recycled
What are three methods for uptake of pathogen prior to presentation by class 2?
Macropinocytosis and clatharin-mediated endocytosis and phagocytosis
Describe protein processing for MHC 2 complex.
Peptide ingested and lysed, invariant chain binds groove, cleaved and leaves CLIP fragment in groove, HLA-DM releases CLIP allowing peptide to bind, exocytosed to surface
What kind of antigens do CD1 molecules present ?
Lipids and glycolipids
What’s the difference between MHC and CD1 in regards to peptide loading location?
Load in endosomes, but still complex with b2m
Which class is cd1 more like?
Class 1
What do cd1c and cd1d present to?
Gamma/delta T cells and NK cells, respectively
What is bare lynmphocyte syndrome type 1?
Defect in TAP proteins, leads to increased bacterial infections, lack of MHC1 and subsequently cd8+ cells, increased NK and gamma/delta T cells to compensate; bone marrow transplant not advised
What is bare lymphocyte syndrome type 2?
Autosomal recessive Defect in class two expression b/c misregulated by RFX complex; leads to normal b and T cell numbers (but cd4 reduced) but severe cellular and humoral immunity depression leading to ubiquitous infection most often GI or respiratory. Treatment is bone marrow transplant
What are two proteosome defect diseases?
CANDLE and Nakajo-Nishimura syndrome
What is self restriction?
positive selection for T cells which react weakly against self MHC; therefore wont attack host; occurs in thymus cortex
What is self-tolerant?
Negative selection for self-reactive T cells; occurs in thymus medulla
What is another name for negative selection?
clonal deletion
When does Th1/Th2 determination occur?
Outside of thymus in periphery when cell binds first antigen
When are T cells considered triple negative T cells?
When in the subcapsular region of thymus and rapidly proliferation