Immune Responses Flashcards
Portion of IgM and IgG that fixes complement
Fc portion
Light chain contribute to what part of the antibody?
Fab portion
4 C’s of Fc portion of antibody
Constant, Carboxy terminal, Complement binding, Carbohydrate side chain
Somatic hypermutation
Increase antibody diversity, this occurs following antigen stimulation
Recombination of VJ
Light chain antibody diversity
Recombination of VDJ
heavy Chain antibody diversity
Part of antibody that recognizes antigens
Variable part of L and H chains
Complement binds where on the antibody?
Y - just below the hinge on the antibody
pretend the Y is the antibody
Macrophage binds where on the antibody?
Y - halfway point of the stem of the antibody
pretend the Y is the antibody
Antigen binding site on the antibody
Y - on either of the top 2 tips of the antibody
Mature B cells express these 2 Igs on their surface
IgM and IgD
Isotype Switching
Gene rearrangement mediated by cytokines and CD40 ligand into plasma cells that secrete IgA, IgE or IgG
Main antibody in secondary (delayed) response to an antigen
IgG
Most abundant Ig in serum
IgG
Crosses placenta to provide infant with passive immunity
IgG
Opsonizes bacteria, neutralizes bacterial toxins and viruses
IgG
Prevents attachment of bacteria and viruses to mucous membranes
IgA
IgA in circulation and when secreted
Circulation - monomer
Secreted - dimer
Most produced antibody
IgA
Early in breast milk, colostrum
IgA
How IgA crosses epithelial cells
Transcytosis
Produced as primary (immediate) response to an antigen
IgM
fixes complement but does not cross placenta
IgM
pentamer
IgM
Binds mast cells and basophils
IgE
Ig in type I HS
IgE
IgE activates this cell type when wormies are around
Eosinophils
Lowest Ig in serum
IgE
Prolonged elevation of serum amyloid A
amyloidosis
Measured clinically as a sign of ongoing inflammation
C-reactive protein
Binds and sequesters iron to inhibit microbial iron scavenging
Ferritin
Coagulation factor; promotes endothelial repair
Fibrinogen
Prevents release of iron bound by ferritinand will cause anemia of chronic disease
Hepcidin
Internalized by macrophages to sequester iron
Transferrin
IgG or IgM mediated complement pathway
Classical pathway
Mannose or other sugars on microbe surface activate this complement pathway
Lectin Pathway
Microbe surface molecules activate this pathway
Alternative pathway
Complement(s) in anaphylaxis
C3a, C4a, C5a
Neutrophil chemotaxis
C5a
Cytolysis of membrane attack complex
C5b-9
Two primary opsonins in bacterial defense
C3b and IgG, C3b also helps clear immune complexes
Used to help prevent complement activation on self cells
Decay-accelerating factor (DAF) and c1 esterase inhibitor
C1 esterase inhibitor deficiency
Causes hereditary angioedema. ACE-I are contraindicated
Increase risk of severe, recurrent pyogenic sinus and respiratory tract infection; increases susceptibility to type III HS reactions
C3 deficiency
C5-C9 deficiencies
increased susceptibility to recurrent Neisseria bacteremia
Causes complement-mediated lysis of RBCs and paroxysmal nocturnal hemoglobulinuria
DAF (GPI anchored enzyme) deficiency
Osteoclast-activating factor
IL-1
Activates endothelium to express adhesion molecules; induces chemokines secretion too recruit leukocytes
IL-1
Causes fever and stimulates production of acute-phase proteins
IL-6
interleukin that is a major chemotactic factor for neutrophils
IL-8
Induces differentiation of T cells into Th1 cells/ Activates NK cells/ Also secreted by B cells
IL-12
Mediates septic shock, activates endothelium, causes leukocyte recruitment, vascular leak
TNF-alpha
Cytokines secretes by macrophages
IL-1, IL-6, IL-8, IL-12, TNF-alpha
Supports the growth and differentiation of BM stem cells.
IL-3
Secreted from Th1 cells
IFN-gamma
Effects of IFN-gamma
antiviral and anti-tumor properties
activates NK cells to kill virus-infected cells
increases MHC expression and antigen presentatio in all cells
Secreted from Th2 Cells
IL-4, IL-5, IL-10
IL-10 and TGF-beta share this feature
inhibit inflammation
Enhances class switching to IgE and IgG
IL-4
Enhances class-switching to IgA and stimulates the growth and differentiation of eosinophils
IL-5
T reg secretes this Interleukin
IL-10
Glycoproteins synthesized by viral-infected cells
IFNs
RNAase L
released from interferons to degrade viral/host mRNA
IFNs secrete Protein kinase to:
inhibit viral/host protein synthesis
CD28 from T cell binds to:
B7 on APC
Receptor for EBV
CD21 on B cell
CD19, 20, 21, 40
B cell surface proteins
CD14, 40, MHC II, B7, Fc and C3b receptors
Macrophage surface proteins