lecture 6- antibodies and antigens Flashcards
what group of globulins are most Abs found
gamma globulins
how are the chains of Abs held together
covalent disulfide bridges as well as by non covalent interactions
what is the difference between the V and C regions
V regions contain the Ag-binding site and C region determines the fate of the Ag
how does the heavy chain C region of secreted IgG end
in tail pieces
what anchors the molecule in the plasma membrane for membrane bound IgM on B cells
a C-terminal transmembrane and cytoplasmic portions
what does papain digestion of IgG allow
separation of 2 Fab fragments and complement- and Fc receptors-biding the Fc fragment
what does proteolysis of IgG by pepsin generate
a single bivalent antigen-binding fragment
define affinity
tightness of Ag-Ab binding
define valence of an Ab
the maximum number of antigenic determinants with which it can react
how many Fab regions does IgG have
2 Fab regions
what does avidity depend on
affinity of the Ab for the epitope and the valence of both the Ab and Ag
what happens to the functional antigen recognition and effector functions when there is an affinity maturation (somatic mutations in variable region) of the antibody structure
functional: increased affinity; effector: no change
what happens to the functional antigen recognition and effector functions when there is a change from membrane to secreted form of an antibody
no change in functional antigen recognition and effector function change: change from B cell receptor function to effector function
what happens to the functional antigen recognition and effector functions when there is isotype switching in Abs
no change in functional antigen recognition but the effector function changes because each isotype serves a different set of effector functions
what are the proliferation cytokines
IL-2, IL-4, IL-5
what are the differentiation cytokines
IL-2, IL-4, IL-5, TNF-gamma, TGF-beta
where is IgA most common
mucosal secretions
where is IgM mainly found
plasma
where is IgE absorbed
surface of fast cells
what is the molecular weight of IgM, IgD, IgG, IgA, and IgE, respecitively
970, 184, 150, 160, 188
what is the most abundant Ig in the blood
IgG
what provides the bulk of immunity to most bloodborne pathogens
IgG
what Igs can Naive B cells express
both IgM and IgD and both are specific for the same Ag
what is the primary function of IgD
Ag receptor on B lymphocytes, but is probably also involved in regulating B cell function when it encounters Ag
