Antibody Function Flashcards
what is the strength of the interaction between the antibody and antigen referred to as?
affinity
does the ability of antibodies to bind using multiple antigen binding sites affect the strength of the interaction?
yes, greatly increased with multiple
in the primary response, what immunoglobulin class is mostly present?
IgM
what immunoglobulin classes are produced in the secondary or memory response?
IgA, IgE, and IgG
what is the change in antibody class produced called?
class switching
why are the antibodies of the memory response higher affinity than those of the primary response?
somatic hypermutation
how does an antibody neutralize a virus/toxin/bacteria?
binding to it and blocking it (not called neutralization for bacteria)
what immunoglobulin classes are most important in neutralization?
IgG and IgA
what is opsonization?
coating of particle with antibody to enhance phagocytosis
phagocytic cells have _____________ that bind to the _____________ of antibodies
Fc receptors
Fc region
what antibody class is most important in opsonization?
IgG
what is opsonization typically directed against?
bacteria, but viruses and other particles (extracellular) can be too
what cells does antibody-dependent cell-mediated cytotoxicity involve?
natural killer cells
virally infected cells and tumor cells
what antibody class is most important in antibody-dependent cell-mediated cytotoxicity?
IgG
what is the most important substance that mast cells release (via degranulation)?
histamine
what are mast cells important in protecting against?
parasites
what antibody class is important in mediating mast cell degranulation?
IgE
what is the major mechanism of allergy?
IgE-mediated hypersensitivity
what does the complement system do?
mediates host defense against various extracellular pathogens, especially bacteria
what do chemoattractants do?
direct migration of phagocytic cells towards the site of complement activation
what antibody classes can activate the complement system?
IgG and IgM
what is the major immunoglobulin in the blood and tissues, but not mucosal surfaces?
IgG
where are IgM pentamers mainly confined to?
bloodstream
what are the major immunoglobulins in mucosal secretions?
IgA dimers
how does IgA get to the tract lumen?
binds a polymeric Ig receptor on the basolateral face of an epithelial cell, undergoes transcytosis within vesicles in the cell, then released at the apical surface into the tract lumen
how is maternal IgG transferred to the fetus in dogs and cats?
some through placenta, mainly through cololstrum
what is the predominant antibody in the colostrum of dogs, cats, ruminants, horses, and pigs?
IgG
what receptor does the human placenta have that allows IgG to be transported across the placenta?
neonatal Fc receptors
what is antibody-dependent cell-mediated cytotoxicity?
natural killer cells stimulating apoptosis in cells coated with IgG (virally infected or tumor cells)
what are the specific receptors on mast cells and natural killer cells bind to their immunoglobulins?
IgE binds to Fc-epsilon receptors on mast cells
IgG binds to Fc-gamma receptors on natural killer cells
what animals are born with maternal IgG?
humans, rodents, non-human primates
what antibody class(es) can cross the placenta?
IgG
what is the predominant antibody in the colostrum of dogs, cats, ruminants, horses, and pigs?
IgG
