Exam 3: Humoral Immune I Flashcards
Passive humoral immune response
artificial
natural
artificial - immunoglobulins
natural - transplacental, colostrum, egg
Active humoral immune response
artificial
natural
artificial - vaccination
natural - diseases
B lymphocyte antigen receptors
characteristics (4)
200,000 - 500,000 BCRs on cell membrane
antibodies are soluble BCRs
all BCRs are antibodies
BCR and antibodies belong to superfamily of proteins: immunoglobulins
BCR strucutre
2 light chains and 2 heavy chains
what attaches light chain to heavy chain
light chain protein attached to heavy chain protein by disulfide bonds
what attaches heavy chains together
disulfide bonds attach heavy chains together
how many constant domains and variable domains in heavy and light chains
Light chain: 1 constant domain, 1 variable domain
Heavy chain: 3-4 constant domains, 1 variable domain
Fab and Fc
Fab is fragment antigen-binding
part of BCR above hinge region
Fc is fragment crystallization
part of BCR below hinge region
what is hinge region
part of heavy chain where disulfide bond is that connects the heavy chain
what enzyme causes fragmentation of antibody
papain or pepsin
breaks antibody into Fab and Fc
which fragment is more antigenic
Fc - because bigger and more constant
which fragment is used to avoid immune reaction in a receptor animal
Fab - smaller, has variable portions
Light chain domains
constant domain C1 (CL)
variable domain V1 (VL)
Light kappa chain (k)
Light lambda chain (λ)
Both light chains are the same, either both lambda or both kappa
Heavy chain domains
4-5 chains domain
always 1 variable, domain 3-4 constant domains
variable domain VH
Constant domain CH
five different types of heavy chain domains
alpha (α) -- IgA
gamma (γ) -- IgG
delta (δ) -- IgD
epsilon (ε) -- IgE
mu (μ) -- IgM
both heavy chains are the same - both alpha, both gamma, both delta, both epsilon, or both mu
variable domain - hypervariable regions
AKA complementary determining regions (CDR)
3 regions (CDR1, CDR2, CDR3)
highly variable areas of variable domain
variable domain - framework regions
between hypervariable regions
relatively constant areas of variable domain
epitope-variable domain interaction
complementary determining regions come together with epitope
when epitope not there the space is called a paratope
like a lock and key
key is the epitope, lock is the receptor
need correct epitope for a specific receptor
what part of the antibody does the antigen bind to
the variable domain
differences between different types of heavy chains
alpha, gamma, and delta heavy chains – 3 constant domains –> CH1, CH2, CH3
mu and epsilon heavy chains – 4 constant domains –> CH1, CH2, CH3, and CH4
what part of antibody is the antigen binding site
VH + VL
what part of antibody stabilizes the antigen binding site
CH1 + CL
Why do IgG and IgM antibodies have complement activating regions
IgG and IgM can activate the classical pathway of the complement system
Which part of the antibody can move
Fab part can move in order to have better interaction with the antigen
both Fab parts can move
what “CD” is present on all B cells and not present on T cells
CD 79
if want to find only B cells can use antibody against CD 79
CD 21 and CD 19 interaction
CD 21 - complement receptor for C3d
CD 19 - signaling component
CD21 binds to C3d
Signaling through CD19, it generates a potent costimulatory signal to enhance B cell responses
B cell crosslinking
Activates B cells
Triggers cell division, differentiation, and immunoglobulin synthesis
both NF-kB and NF-AT are involved in B cell signal transduction
