Basic Science II & III Flashcards
CD19 expression stops at what stage of B cell development?
Plasma cell
What process determines if an Ig will be membrane bound or secratory?
alternative splicing
Failure to limit RAG mediated rearrangement of VDJ can lead to what pathology?
lymphoma
How does Rituximab target B cells without affecting T cells?
Target is CD20 - only present on B cells
Where do B cells reside before they have encountered antigen?
primary follicle
Which growth factors are secreted by dendritic cells to allow for B cell survival?
BLyS (BAFF) and APRIL
What 3 CD markers comprise the B cell receptor complex?
CD19, CD21, CD81
How is the B cell activation amplified?
CD19,21,81 complex provides second signal by activating ITAM
How is the B cell activation signal downregulated?
IgG bound to antigen binds to FCγRII, activating ITIM
What type of antigen do marginal zone B cells recognize?
polysaccharide
What type of antigen do conventional B cells (B-2 cells) recognize?
protein antigen
What is the purpose of somatic hypermutation?
affinity maturation
Which which enzymes are used in class switching?
AID (instead of RAG) and UNG
Which immunoglobulin is not produced by recombination?
IgD - occurs via alternative splicing
Is somatic hypermutation T cell dependent or independent?
dependent
Is B cell activation and development into short lived plasma cells or long lived B1 cells T cell dependent or independent?
independent
How does CD40 ligand deficiency result in hyper IgM syndrome?
failure to receive T cell help
Deficiency of AID or UNG results in what disease?
Hyper IgM syndrome
What surface marker identifies a B cell as a memory B cell?
CD27
TLR3 recognizes what?
viral ds RNA
TLR1/2 recognizes what?
lipopeptides from bacteria
TLR2/6 recognize what?
peptidoglycan and heat shock protein
TLR4 recognizes what?
LPS
TLR5 recognizes what?
flagellin
TLR7/8 recognize what?
ds RNA
TLR9 recognizes what?
viral DNA
Which TLRs bind intracellular targets?
TLR3, 7, 8, 9
What is the main transcription factor that is activated through TLR signalling?
NF-κB
Which TLR functions through a MyD88 independent process, and what does it use instead?
TLR3 (TLR4 can fxn with or without MyD88); TRIF -> TRAF3
MyD88 transmits a TLR signal to what?
IRAK4
TLR4 pair with what 2 other molecules to generate a response to LPS?
CD14 and MD2
NF-κB induces production of what cytokines?
TNF, IL-1, IL-6, IL-12
In addition to NF-κB, what other transcription factors are activated via TLR signalling?
IRF3 (Interferon regulatory factor) IRF7, IRF5, AP-1
What fusion gene is associated with hypereosinophilic syndrome and predicts response to imatinib?
PDGFRA
What is the function of CXCL8?
neutrophil chemotaxis
What is the function of CXCL10?
T cell chemoattractant - induced by interferons
What is the function of CX3CL1 (fractalkine)?
acts as adhesion molecule and chemoattractant for monocytes and T cells
What is the ligand for P-selectin?
Sialyl-Lewis X
What is the ligand for ICAM-1?
LFA-1, Mac-1, fibrinogen
What does rhinovirus use to gain entry into cells?
ICAM-1
CCR4 binds to what ligands?
CCL17 and CCL22
What is the receptor used by Plasmodium vivax to infect red cells?
DARC
What molecules on a T cell does HIV use to gain entry into T cells?
CXCR4, CCR5, CD4
What are the molecules on HIV that attach to a T cell?
gp120 and gp41
What mutation is associated with resistance to HIV?
CCR5
What mutation is associated with more aggressive HIV disease?
CCL3L1
Phosphorylation of an ITIM leads to recruitment of what?
SHP-1&2, SHIP
Which tyrosine kinase binds to the cytoplasmic domain of CD4 and CD8?
p56lck
During T cell activation, hydrolysis of PIP2 by PLC gamma generates DAG and IP3. What do DAG and IP3 do?
DAG - modulates NFkappaB pathway
IP3 mediates Ca+ influx
In T cell activation, where does the initial increase in Ca+ come from?
Endoplasmic reticulum
In T cell activation, Ca+ release from the ER activates what to further increase Ca+?
CRAC channel
In T cell activation, Ca+ influx activates what?
calcineurin
What does calcineurin do?
dephosphorylates NFAT during T cell activation allowing it to be transferred to the nucleus
MAP kinase pathways activate which transcription factors during T cell activation?
Fos and Jun, which leads to AP1 activation