Flashcards in L5 Deck (28)
What are the 5 things that can happen after an Ab binds an antigen?
3. Mast/eosinophil activation
4. Classical complement
5. Mucosal and placental transport
What Abs target an antigen for neutralization?
What Abs target an antigen for opsonization?
What Abs target an antigen for mast cell/eosinophil activation?
What Abs target an antigen for complement activation?
What Abs target an antigen for mucosal transport?
What are the structural differences between Ab isotypes?
Varying Fc lengths
Different carbohydrate patterning
When you talk about Abs neutralizing antigens, explain some ways that could occur.
Ab (IgA/M/G) blocks:
- Microbe getting through epithelium
- Microbe binding other cells and infecting them
- Binding to cellular receptors
What molecules can opsonize Ab-antigen complexes if stimulated by IgG1/G3? What receptors do these Abs need for each binding option?
Fc gamma receptors
1. Bind Fc GAMMA R2A = NK cell kills the antigen attached
2. Fc GAMMA R1 = macrophage phagocytosis
What kind of antigens are targeted by IgE for mast cell or eosinophil degradation?
What happens if you get IgE mediated hypersensitivity reactions?
What receptor binds IgE?
Fc receptors is the general name for receptors that bind Abs - because they bind the effector region of the Ab, the Fc region. What molecules carry out the functions of these receptors?
ITAM = activating
- The tyrosine residues within these motifs become phosphorylated following interaction of the receptor molecules with their ligands and form docking sites for other proteins involved in the signaling pathways of the cell.
ITIM = inhibitory
- ITIM motif becomes phosphorylated by enzymes of the Src kinases, --> recruit phosphatases decrease the activation of molecules involved in cell signaling
What is the one inhibitory Fc gamma receptor? (Has ITIM associated with it)
Fc gamma R2B
What 2 molecules help IgA move an antigen across mucosal epithelium? Which cells make each?
J chain - made by B cells
Poly-Ig receptor - made by epithelium
What is the neonatal Fc receptor?
Binds IgG transports across placenta
How does the polio vaccine work?
Mucosal IgA neutralizes virus
How does the tetanus vaccine work?
How does the Hep A or B vaccine work?
How does the pneumococcal pneumonia vaccine work?
IgM & IgG - opsonization & phagocytosis
Direct or via complement
What are gamma delta TCRs?
Recognize weird molecules
MHC 1-like molecules w/o anything bound
What are iNK TCRs?
LIPID piece of antigen
Presented by CD1d
What part of the receptor is expressed in preT/B cell receptors?
- High or low surface expression?
- Always on the cell surface?
- Binds ligand?
IgH / TCRbeta chain expressed 1st
VpreB / preTalpha surrogates there as place holders
- LOW surface expression
- Continuously recycled on/off the membrane - spontaneous incorporation into lipid rafts
- NO known ligand
Describe what happens when B cells bind antigen for the first time in the periphery.
Phagocytosis - acts as an APC
Presents molecules on MHC 2 - because was a free floating, extracellular molecule
Connects with helper T cell
Helper T cell differentiates depending on what the antigen presented was
Th makes cytokines that makes B cell --> plasma cell --> MORE Abs
If the innate cells binds PAMPs, what do adaptive cells bind?
Do BCRs or TCRs recognize free antigens?
TCRs - processed antigen via APC
What molecule is key for vaccine development?
Hapten = small molecule + carrier protein