Immunology 3 Flashcards
IRAK-4 deficiency - what infections prone to?
Pyogenic infections
Major receptors to capture fungal?
Dectin 1/2 - then stimulate Th17 differentiation
NOD-like receptors function?
Assemble inflammasome and signal Nf/MAPK pathway
Inflammasome senses DAMP/PAMP and activate caspase 1 = releases IL1
Familial Mediterranean fever mutation and pathogenesis?
Clinical features?
Mutation of Pyrin gene - pyrin is inflammasome = triggers pyroptosis
Clinical features
-Fever/Serositis/Arthritis
Hyper Ig-D syndrome pathogenesis?
Defective RHoA = Pyrin very active and inflammasome = pyroptosis
Eg. of HAMP = Homeostasis altering molecular process
How NOD2 contributes to Crohn’s disease?
NOD2 in Paneth cells of terminla ileum = produces AMP - antimicrobial peptide duhhh ( products against bacteria) and cause Autophagy of bacteria
Crohns has dysfunctional NOD2
IL1 function in innate immune?
Increases expression of adhesion molecules - transmigration leucocytes to infection site = fever!
Most potent source of Interferon?
Plasma Dendritic Cells
Most potent source of Interferon?
Plasmacytoid Dendritic Cells
Summary of Innate immune system components and function?
CLR = Glue ( stick to pathogens) NLR = Inflammasomes - caspase 1 releases IL1 TLR = cell activators (Gram -ve, stimulate B cells) RLR = RNA sensors in cytoplasm - release IL1 AIM2/cGAS = DNA sensors in cytoplasm
Chronic granulomatous disease
- Nitroblue tetrazolium check what?
- Flow cytometry check what?
- Nitroblue checks activated neutrophils
- Flow cytometry checks dihydrorhodamine ( burst neutrophils)
What are chemokines?
directs movement of leucocytes eg. CCR5/CXCR4
What activates NK cell to kill?
ADCC - antibody dependent ( Ig G and Ig E)
Activating receptors - bind to viral proteins
Devoid of MHC I ( cancer/virus) - so NK will attack yum yum
Cytokines - chemokines
Ig G does what?
Ig M does what?
Ig A does what?
Ig G - complement, Opsonisation/neutralisation
Ig M - complement, Agglutination ( low affinity, high avidity)
Ig A - inhibit colonisation and binds to mucus to trap pathogens
what site of Antigen binding on Ig most variable?
Memory B cells express what CD?
CDR3
Memory B cells = CD27
what is Hapten?
Small molecule ( no immune response) but when linked to large molecule ( carrier ) = elicits immune response
Common variable immunodeficiency (CVID) a/w what Ig?
Ig A deficiency
Ig G subclass deficiency - treatment?
Ig A subclass deficiency - important to take note regarding infusion?
Ig G - tx is IVIG
Ig A - mucosal defect, if give infusion needs Ig A deficient donor or triple wash product
2 types of Antibody forming cells from B cells ie;
Plasmablasts
Plasma cells
-function and characteristics?
Plasmablasts = Rapid activation, short lived, Ig M secretion
Plasma cells = activated from germinal centre, long lived, reside in bone marrow, secretes all antibodies!
B-cell lymphoma means?
clone of identical B cells having = Identical VDJ rearrangement ( heavy chain)
Heavy chain ( VDJ rearrangement) mediated by? and B cell becomes?
Light chain ( VJ rearrangement) mediated by? and B cells becomes?
Heavy Chain - RAG genes = Pre-B cell
Light chain - Rag-mediated = Immature naive B cell ( express surface Ig M)
B Agamaglobulinemias vs X-linked agammaglobulinemia?
B-agamma = Btk deficiency = No B cells, No Ig
X-linked agamma = Btk MUTATION = No B cells, No IgG, EPG = hypogamma
B Agamaglobulinemias vs X-linked agammaglobulinemia?
B-agamma = Btk deficiency = No B cells, No Ig
X-linked agamma = Btk MUTATION = No B cells, No IgG, EPG = hypogamma
Mature B cells have what expression Ig?
Mature B cell = Ig M and Ig D
Mature B cell needs T cell co-stimulation to do what?
Activation and proliferation
Differentiate into memory B cells and Antibody forming cells
Undergo somatic hypermutation to gain isotype switching and affinity maturation
What happens in Hyper Ig M syndrome?
clinical features?
Tx?
Absence of CD40 and CD40L stimulation - so no somatic hypermutation/no isotype switching/ no Immunoglobulin/ no memory B cells
- Neutropenia and recurrent bacterial infections ( PJP!)
- Low Ig A,G,E
- Ig M Very HIGH, Ig D normal
Tx- IVIG and bactrim prophylaxis
Ig M is what affinity, avidity?
Ig G is what affinity, avidity?
Ig M is low affinity ,HIGH avidity
Ig G is HIGH affinity, HIGH avidity
EBV enters and infect B cell via CD what?
CD21 - 3D receptor
How B cell activated without T cells?
TLR
Multiple repetitive polysaccharides
Which T cells facilitate allograft rejection?
CD4 - T helper cells
T cells undergo what type of somatic changes?
Somatic rearrangement
How T cell activated without APC/MHC presentation?
Super-antigens bind to MHC: peptide groove
- Toxic shock syndrome
- Staphylococcus enterotoxins
