Exam 2- Antibodies and the memory response

secreted immunoglobin proteins

extracellular spaces

heterodimer with 2 light chains (22kda) and 2 heavy chains (55kda) joined by a disulfide bridge; variable ends are the first 110 a.a. of amino terminal (specificity)

110 a.a. on amino-terminal of both chains

generates Ig diversity; makeup the variable region

constant region-binds the immune cells (macrophages) and reacts with complements

circulate blood seaking target antigen, find, bind, and mark for destruction(5 ways)

Agglutination Fixes and activates complement Opsonization Neutralization Antibody dependent cell mediated cytotoxicity

crosslink antigen to reduce number of infectious units (clump)-able b/c 2 binding sites

activate complement via CLASSICAL pathway—–ab binds to antigen on pathogen and activates formation of C3 convertase to activate MAC and inflammation

classical pathway

coating antigen w/ antibody which enhances phagocytosis (IgG and C3B); Phagocytes have Fc receptor that binds IG (bound to antigen) causes phagocytosis

IgG on opsonized antigen for phagocytosis; or to Ab in the case of antibody dep. cell mediated cytotoxicity

blocks adhesion of bacteria and viruses to mucosa, blocks attachment of toxins (no longer can act on host cells)

target cells for destruction by eosinophils and NK cells——Eosinophils have Fc receptor that binds Ab, recognizing antigen on large pathogens (worms)— secretes perforin and granzyme; NKs can recognize Ab on antigens too!

Antibody dependent cell mediated cytotoxicity

5 ISOTYPES

the a.a. sequence in the constant region of the heavy chain

monomeric; secreted is pentameric

expressed on B cells (BCR), Activates compliment, good at agglutination (can bind 10) and is first class produced in primary response

IgM

IgG

IgG-very small

IgG and IgM