Compliment Flashcards
CD40
receptor on B-cells that is activated by CD4 T cells to differentiate to plasma cells
B-cell activation
Ag binds BCR and is presented on MHC 2 then CD4 T2H T cell binds correct Ag and delivers CD40L to activate plasma cell differentiation
B-cell clonal deletion
if the B-cell has low affinity immunoglobulin it fails to cross link with T cell and dies
B-Cell differentiation
B-cells with high affinity Ig become memory cells or plasma cells
IgM secretion
plasma cells in bone marrow (only type released here), spleen and lymph nodes
FcRn (brambell receptor)
Transporter similar to MHC 1 molecule that transports IgG into extracellular tissue space for more coverage
FcRn function
generic endocytosis occurs where the acidic pH triggers IgG binding to FcRn and prevents proteolysis. Basic pH of extracellular fluid causes release
transcytosis
Poly-Ig receptor on basolateral surface of epithelial cells bind dimeric IgA, the secretory piece binds to IgA and mucus to prevent dissociation away from the mucus membrane
IgA locations
epithelia linings, faces, sputum, tears, breast milk
maternal protection
FcRn also allows for transport across the placenta giving baby equal amounts of IgG to mother.
IgA is transfered through breast milk during feeding
infant Aby production
IgM production starts soon after birth with IgG about 6 months later.
Neutralization
Via Aby either blocking virus receptor binding or bacterial adhesions to prevent colonization
opsonization
Aby mark bacterium for phagocytosis and death
neutrophils, monocytes and macrophages have Fc receptors specific to certain isotypes
IgG opsonization
activate macrophages, neutrophils, eosinophils and dendritic cells
cause respiratory burst to kill
IgE opsonization
Bind almost pertinently
activate mast cells, eosinophils, basophils and FDCs. cause granule secretion
IgA opsonization
activate macrophages, neutrophils and eosinophils
induce uptake to kill
Mast cell activation
Via multivalent Ag crosslinks from IgE binding to Fc-epsilon-R1 receptors
Mast cell granules
histamine and Inflamm soup to increase BV permeability, very fast response to Ag and targets parasites
ADCC
Aby-dependent cell-mediated cytotoxicity, via Nk cells granzyme triggered apoptosis
Natural killer cellss
Lymphocytes with no TCR or surface Ig, operates for innate immunity expressing Fc-gamma receptor that targets Aby coated human cells for death
Complement production
Glycoproteins all synthesized in the liver, produced as inactive zymogens until cleaved
Complement sequence
1,4,2,3,5,6,7,8,9
factors B,D,H,I,P
mannose binding lectin MBL
Classical pathway
Ag binds antigen which opens up C1 binding sites, C1 cleaves and joins C4b which cleaves and joins C2a forming the C3 convertase to populate the surface with cleaved C3, then adds C3b to create C5 convertase to complete MAC formation
C4b2a
C3 convertase for classical and lectin pathway
