A 7 Flashcards
how does mycobacterium tuberculosis live within a phagocyte and not die?
it prevents the fusion of phagosome with the lysosome.
many bacteria that can live within a phagocyte survive because they escape into the cytoplasm. Name 4 common bacteria that do this?
1) salmonella
2) legionella
3) Francisella
4) Listeria
(note: viruses can also do this)
how does salmonella make you sick?
It gets phagocytosed but does not die because it escapes into the cytoplasm. It can live within all phagocytic cells and B cells.
what is the difference between a NOD like receptor and a TOLL like receptor?
NOD receptors are free floating in the cytoplasm looking for foreign anigen.
TOLL receptors are looking for pathogen on the outside surface as well as inside vesicles.
What do NOD’s detect?
NOD’s detect peptidoglycan (NAG and NAM) of bacterial cell walls.
What does NOD1 do? Which bacteria would this include?
senses gamma glutamyl diamino group. (Bridge between NAM molecules)
salmonella and listeria.
what does NOD2 do?
senses muramyl dipeptide (NAM)
The LRR and CARD (Caspase attracting) domains make up which molecules?
NOD like receptors (which also have a NOD domain of course)
Once NOD binds, it dimerizes and binds to _______This then leads to the activation of ______ which ultimately makes _________ for cytokine production?
1) RIP2K
2) TAK1
3) NFkB
What is NLR-P3 (NALP3)?
It senses celluluar damage or stress.
What forms when NALP3 is bound to the protease caspase1?
inflammasomes are released. Two mentioned were IL 1 and IL18
what is the function of caspase 1?
cleaving of pro-inflammatory cytokines (activate)
DNA cleavage
Induce cell death.
what happens during NALP3 (NLRP3) activation?
1) cell distress
2) NALP3 recruits PYCARD/Caspase complex
3) activation of caspase 1 through interaction.
4) Caspase 1 cleaves pro-inflammatory
5) release of inflammatory cytokines (including IL 1 and IL 18) to cell surface and cell death.
What is pyroptosis?
inflammation and cell death.
what is the purpose of MHC?
1) to determine self from non-self (type 1)
2) determines the strength of adaptive immune response. (type 2)
What are the two groups of Human leukocyte antigen (HLA) called? What chromosome is HLA found on?
1) MHC1
2) MHC 2
- chromosome 6 and invariant region of MHC 1 is on chrom. 15
what are the three subtypes of Class 2 MHC? Which one has 2 copies of its B subunit?
Dp, Dq, Dr (within each subtype there are many alleles)
-Dr has two copies of its B subunit while the rest only have one
what are the three subtypes of Class 1 MHC?
A,B,C (within each subtype there are many alleles)
What is B2 microglobulin?
The second part of MHC class 1 molecules. They help with surface expression and stability.
How are class 1 and class 2 molecules expressed in human cells?
codominantly, with 6 (class 1) alleles, and up to 25 (class 2) alleles.
Class 1 MHC determines?
You from not you
Class 2 MHC determines?
the strength of an immune response.
which types of cells express MHC type 2?
dendritic cells, macrophages, B- cells, or any cell that presents.
Which cells target the foreign MHC class 2 molecules?
The T-cells with CD 4 receptors to initiate the adaptive immune response.
which MHC class binds to self and non-self peptides that are generally 8-10 AA’s long?
Class 1 MHC
which MHC class binds to self and non-self peptides that are generally 15 AA’s long?
class 2 MHC
Which cells target the foreign MHC class 1 molecules?
CD 8 T-cells to attack things like intracellular pathogens and donor transplants.
How does MHC 1 become expressed on the cell surface?
1) calnexin bound to pre-MHC1 in E.R.
2) calnexin releases Pre-MHC1 once it binds B-microglobulin.
3) MHC 1binds TAP
3) TAP transports random peptide fragments into ER to become part of MHC 1 complex active site.
4) MHC complex is sent to cell surface for Identification. (NOTE: samples endogenously)
How does MHC 2 become expressed on the cell surface?
1) Stuck to ER membrane with active site blocked by invariant chain.
2) Invariant chain cleaved off in acid endosome except part in cleft which is called Clip.
3) Endocytosed peptides are broken down and placed in same vesicle.
4) HLA-DM binds to MHC 2 complex displacing Clip.
5) foreign peptide binds to MHC 2
6) MHC with foreign antigen placed on membrane.
What are the primary lymphiod tissues?
Thymus and bone marrow
What are some examples of secondary lymphoid tissues?
Lymph nodes, spleen, liver, and MALT/GALT/SALT
What are the subunit sizes for MHC Class 1 and Class 2? (The alpha and beta subunits)
- 43 K and 12 K respectively a and b
- 28 K and 32 K
