2.4 Flashcards
b cell receptor:
forms of antigens recognized
macromolecules
small chemicals
conformational and linear epitopes
b cell receptor:
diversity
each clone has a unique specificity; potential for >10^9 distinct specificities
b cell receptor:
antigen recognition is mediated by:
variable regions of heavy and light chains of membrane Ig
b cell receptor:
signaling functions are mediated by:
proteins associated with membrane Ig
b cell receptor:
effector functions are mediated by:
constant regions of secreted Ig
t cell receptor:
forms of antigens recognized
mainly peptides displayed by mhc molecules on APcs
linear epitopes
t cell receptor:
diversity
each clone has a unique specificity; potential for >10^11 distinct specificities
t cell receptor:
antigen recognition is mediated by:
variable regions of alpha and beta chains of the TCR
t cell receptor:
signaling functions are mediated by:
proteins associated with the TCR
t cell receptor:
effector functions are mediated by:
TCR does not perform effector functions
CDRs =
3 variable
antigen-binding
loops
isotype of antibody: IgA subtypes (H chain): serum concentration (mg/mL): serum half life (days): secreted form: functions:
IGA 1, 2 3.5 6 mainly dimer, also monomer, trimer mucosal immunity
isotype of antibody: IgD subtypes (H chain): serum concentration (mg/mL): serum half life (days): secreted form: functions:
none trace 3 monomer naive b cell antigen receptor
isotype of antibody: IgE subtypes (H chain): serum concentration (mg/mL): serum half life (days): secreted form: functions:
none 0.05 2 monomer defense against helminthic parasites, immediate hypersensititivty
isotype of antibody: IgG subtypes (H chain): serum concentration (mg/mL): serum half life (days): secreted form: functions:
IgG 1-4 (gamma 1, 2, 3, 4) 13.5 23 monomer opsonization, complement activation, ab dependent cell mediated cytotoxicity, neonatal immunity, feedback inhibition of B cells
isotype of antibody: IgM subtypes (H chain): serum concentration (mg/mL): serum half life (days): secreted form: functions:
none 1.5 5 pentamer naive b cell antigen receptor (monomeric form), complement activation
Generation of hybridomas and monoclonal antibodies
isolate spleen cells from mouse immunized with antigen C
fusion
fuse spleen cells and immortal myeloma cell line
culture in selection medium
only fused cells (hybridomas) grow
isolate clones derived from single hybridoma cells
screen supernatants and expand positive clones
hybridomas producing monoclonal anti-x antibody
featureL
immunoglobulin (Ig)
T cell receptor (TCR)
feature: antigen binding
immunoglobulin (Ig)
T cell receptor (TCR)
made up of three crds in Vh and three crds in Vl
made up of three cdrs in Va and three cdrs in Vb
feature: changes in constant regions
immunoglobulin (Ig)
T cell receptor (TCR)
heavy chain class switching and change from membrane to secretory Ig
none
feature: affinity of antigen binding
immunoglobulin (Ig)
T cell receptor (TCR)
Kd 10^7-10^11 M; average affinity of Igs increases during immune responses to protein antigens
Kd 10^5-10^7 M; no change during immune responses
feature: off rate and on rate
immunoglobulin (Ig)
T cell receptor (TCR)
rapid on rate, variable off rate
slow on rate, slow off rate
Steps in maturation of lymphocytes (6)
communitment prolifertion pre-B/T antigen receptor expression proliferation antigen receptor expression positive and negative selection
Steps in the maturation and selection of MHC-restricted T lymphocytes (4)
stem cell double negative pro t cell pre t cell double positive immature t cell mature cd4/cd8/apoptosis
