Kasman Flashcards
What mediates innate immunity?
Epithelial barriers, phagocytic cells, natural killer cells and serum protein called complement
What is a major difference between the pathogens that cell mediated vs humoral immunity defends against?
Cell mediated defends against intracellular while humoral defends against extracellular and they are both types of adaptive immunity.
What mediates adaptive immunity?
T and lymphocytes and their products
What is an immunogen? a hapten? An epitope?
An antigen that can induce an immune response. A hapten is an antigen that cannot induce an immune response. An epitoe is a specific part of the antigen that is recognized.
What are MHC proteins?
Cell surface molecules that present the peptide antigens to T cells
Granulocytes belong to what part of the immune system?
Innate
What are the 3 APCs?
Dendritic cells- present antigens to naive T cells
Macrophages- present antigens to mature T cells
B cells- present to CD4 cells to stimulate the immune response
How do dendritic cells direct the adaptive response?
Present to either MHC 1 (intra) orMHC II (extra)
What is the significance of codominant expression and polymorphic genes in terms of disease fighting ability?
increases the no. of mhc molecules that can present t T cells. polymorphic genes ensure tht diff individuals ar able to respond to diff microbes
Role of Tap 1 in class 1 pathway?
transports peptides into ER to bind to MHC1
What are the two complement inhibitors?Mode of action?
DAF- acts on convertase and CD59 aborts MAC formation
Role of C3a, C5a and C3b?
C3a degranulates mast cells, C5a recruits neutrophils and C3b releases opsonins which increase phagocytosis.
How is a M1 macrophage formed? What does it secrete?
By IFN-gamma and PAMPS> SecreteTNF, IL-1,IL-6 and IL-12
How is a M2 macrophage formed? What does it secrete?
By IL-4, IL-13. Secrete TGF-beta, IL=10 and litlle IL-12
Cell surface mediators of signal 2 are called?
Co stimulatory molecules
What are the two polyclonal activators of T cells?
PHA and Con A..they bind to carbohydrates and elicit activation without the presence of an antigen
Suprantigens crosslink MHC on APC attached to T cell complexes and elicit responses in the absence of a specific antigen
LFA-1?
Important adhesion molecule in cell mediated immunity
Th1? Transcription factor?
A T helper cell, secrets IFN-gamma. Activates killing of phagocytised microbes, induces increased opsonization.
Tbet
Th2? Transcription factor?
Release eosinophils, release IL-4 to anatgonize Th1, non opsonizing. IL-5 induces eosinophils
GATA-3
Th 17? Transcription factor?
Immune respne,recruits neutrophils. ROR gamma T
The PAMP, LPS, which is on the outside of GN bacteria is recognized by what PRR?
CD14
What 4 mediators recruit neutrophils?
IL-8, C5a, LTB4 and bacterial products
Three ways by which mast cells are activated?
Tissue trauma
Complement proteins- C3a, C5a
IgE
Histamines mode of action?
Vasodilation of arterioles and increased permeablity of post capillary venules
Mast cell mechanism?
Early- release of histamines
Late- production of archidonic acid particularly leukotrienes
Key mediators of vasodilation?
Histamine, PGs and bradykinin
Which 2 cells express CCR7?
Naive T cells and dendritic cells
What is the source of proteins for the class i pathway vs the class II pathway?
Class II- endosomal and lysomal proteins while class I- cytosolic proteins
Proliferation of immature lymphocytes is driven by?
IL-7
How are diverse receptors created?
Somatic recombination- that is enzymes catalyze the deletion of DNA to bring different coding sequences together.
Where are the V,D and J cassetes found?
D found in heavy chains and beta of TCR
V and J are found in light chains and alpha of TCR
Combinatorial diversity vs junctional diversity?
Combinatorial diversity- random joining of segments
Junctional diversity- Ligases add nucleotides to the sites. Endonucleases cleave nucleotides and the Tdt enzyme adds them randomly. It provides most of the repertoire