Immuno week 1 - Post Lect. Updates Flashcards
T or F: neutrophils present antigens
False
What cells have IgE receptors?
- Basophils
- Eosinophils
- Mast Cells
What are the first CELLs to act in the innate response?
Neutrophils
What cell type is active throughout the ENTIRE immune response?
NK cells, more geared toward viral infections
What cell in the acquired immune response has a function similar to NK cells?
CD8 T cells
What are the APCs?
B cells
Macrophages
Dendritic Cells
Why are antibodies more geared toward an extracellular response?
- Access, antibodies are released into the extracellular environment and must bind the toxin themselves (they don’t use MHC that gives them a sample of the intracellular environment)
Why are viral responses more T cell driven?
Cells infected with viruses don’t show PRR’s necessarily, therefore the viral proteins that are there will likely get overlooked by macrophages and neutrophils. T cell receptors can sense this though.
Where does antigen presentation take place?
- why?
Takes place in the T-cell zone because this is the area where the highest concentration of T cells exist. If APCs present here then there is a much higher chance of them encountering the appropriate T cell.
What function of the immune system is most compromised by loss of the spleen?
- Phagocytosis
What would happen in the absence of allelic exclusion?
You would get multiple antibodies for cell and the Avidity of the cell for the epitope would be reduced.
What will happen to patients that lack IL-7?
They will have B cells but they will not function
**IL-7 is secreted by the stromal cells and is needed for B cell differentiation
Lack of what enzyme needed for development will lead to low B cell count (of all types)?
Low BTK would lead to low B cell count
RAG deficiency would too
T or F: after moving into circulation, all activities of B cells are antigen independent
True, somatic recombination is the only antigen independent reaction and it occurs during development
What is the use of IgM if it lacks a complement region?
It is used in the complement cascade
What determines antigen specificity?
Antigen specificity is determined by Variable region of Heavy and Light Chains
T or F: a mutation that leads to inability of the intrachain disulfide bond in the light chain would be reason to switch to the Lambda gene
True, but only if this failed on BOTH kappa’s
What is the most devastating affect of AID mutation?
Loss of the ability to switch classes
An enzyme is mutated that leads to low numbers of BOTH B and T cells. What could it be?
RAG1/2
Why do many self-reactive B cells make it out of the the bone marrow?
The Bone marrow is not completely representative of the proteins that will be encountered in the body
What is the most important part of the complement cascade?
C3 opsonization
What does C5a do?
Recruits neutrophils
What is Terminal Complement?
A term that refers to MAC
What does it mean if something can fix complement?
It can kick off the complement cascade (i.e. IgM and to some extent IgG)
What is likely to be your biggest problem if you lose the ability of terminal complement?
MAC is really only VITAL against Niessiera infection in which its actually even more important than C3
T or F: C-reative protein and Mannos-binding lectin are examples of PRRs
True
What is the most important complement protein in capsular detection?
C3b, because it allows for opsonization via macrophages
What is the most important control protein in complement?
Factor I
What cells are most affected by defects in complement control?
Erythrocytes, they will be eliminated because they will bind so much stuff that has C3
What cause HANE?
no C1INH
**would lead to low serum C2 and C4
Why is low MHC class I a marker of a cell that needs to be killed?
Low MHC class I is an indication that a virus has hi-jacked the cell
**Note MIC will eventually get recycled off too
T or F: NK cells alone can clear a viral infection
False
T or F: some defensins are seceted while some are naturally present
True
When do complement proteins get synthesized?
always!!
What are two important chemotractic factors for neutrophils?
IL-8 and C5a
What process allows macrophages, dentritic cells, etc. to get to 2˚ lymph tissue?
Inflammation
T or F: platelets prevent dissemination.
True
Where in/on the cell will you find RIG and NOD?
in the cytoplasm
What causes IL-8 to be release?
Release of IL-6 by macrophages
What dual purpose does an increased temperature serve?
- Better immune response
- Kills bacteria
What do Ig do NK cells recognize?
IgG1 and IgG3 (might want to verify this)
When does the acute phase response occur?
When there’s bacteria in the bloodstream
Where are Toll-like receptors found in/on the cell?
In the cytoplasmic membrane
Whats the purpose of have 3 types of receptors on macrophages (TLR, RIG, NOD)?
TLR - located on the membrane so if its activated then the cell knows its dealing with an extracellular pathogen
NOD, for example, is on the inside leading to signaling that there is an intracellular pathogen
What does TLR 5 recognize?
Flagellin
