EXAM 2 B Cells: Antibodies and Diversity Flashcards
B cells produce one unique ___
antibody
B cells target one antigen ___
epitope
B cells affect extracellular ___
pathogens
B cells have ___ target diversity
infinite
do B cells have high or low probability of reaching maturation?
low
B cells undergo ___ and ___
clonal selection and expansion
B cells improve targeting following ___
activation
B cells can persist for ___
years
what are the 6 phases, in order, of B cell infection response
- repertoire assembly
- negative selection
- positive selection
- searching for infection
- finding infection
- attacking infection
small lymphocytes can produce ___ or ___
B cells (antibodies) or cytotoxic and helper T cells
___ are fully differentiated forms of B cells that secrete antibodies
plasma cells
describe the repertoire assembly phase of B cell infection response
generation of diverse and clonally expressed B-cell receptors in the bone marrow
describe the negative selection phase of B cell infection response
alteration, elimination, or inactivation of B-cell receptors that bind to components of the human body
describe the positive selection phase of B cell infection response
promotion of a fraction of immature B cells to become mature B cells in the secondary lymphoid tissues
describe the searchign for infection phase of B cell infection response
recirculation of mature B cells between lymph, blood, and secondary lymphoid tissues
describe the finding infection phase of B cell infection response
activation and cloncal expansion of B cells by pathogen-derived antigens in secondary lymphoid tissues
describe the attacking infection phase of B cell infection response
differentiation to antibody-secreting plasma cells and memory B cells in secondary lymphoid tissue
which phases of B cell infection response occur in the bone marrow, and which occur in seconary lymphoid tissues?
- phase 1, 2, and 3 occur in the bone marrow
- phase 4, 5, and 6 occur in secondary lymphoid tissues
antibodies are also called ___
immunoglobulins
antibodies are targeted ___
effector proteins
antibodies are ___ specific
antigen epitope
what are the effector functions of antibodies?
- receptors - B cells and granulocytes
- neutralization
- opsonization
- signaling
are antibodies glycoproteins?
yes
describe the theoretical and practical target diversity of antibodies
- theoretical: 1X1016
- practical: 1X109
what are the 3 sources of antiben diversity?
- genetic recombination
- junctional diversity
- somatic hypermutation
antibodies have a ___ chain and a ___ chain
heavy and light
describe the heavy chain of antibodies
- isotype determines antibody class
- receptor interaction
- proportionally small variable region
- binds antigen
describe the light chain of antibodies
- binds antigen
- proportionally large variable region
- two isotypes
- κ
- λ
which isotypes dictate each antibody class?
- γ (IgG)
- μ (IgM)
- δ (IgD)
- α (IgA)
- ε (IgE)
different ___ encode the heavy and light chains
genes
cleavage of an antibody by a protease will result in the production of what?
- one Fc and two Fab fragments
- cleaves at the disulfide bonds
the light chains are at the ___ termini, and the heavy chains are at the ___ termini
- N only
- C and N
what are Fab regions?
antigen binding region (N termini)
what is the Fc region?
conserved region (C termini)
what is the difference between monomeric antibodies, dimeric antibodies, and pentameric antibodies?
- monomeric antibodies have the single antibody
- dimeric antibodies are a complex of two antibodies + J chain (holds the two Abs together)
- pentameric antibodies are a complex of five antibodies + J chain (holds all five Abs together)
antibody functional diversity is determined by the ___ region of the antibody
conserved
which antibody regions bind antigens?
variable regions
what are hypervariable regions?
regions where mutations occur that really effect binding affinity of particular antibodies
what are the 4 main antigen epitopes that antibodies target?
- terminal polysaccharide
- polysaccharide chain
- globular protein surface
- globular protein pocket
___ is a molecule recognized by a B or T cell
antigen
___ is the region of an antigen bound by an antibody or MHC/TCR
epitope
describe the 4 types of epitopes
antibody structure facilitates ___
function
___ production coincides with B cell development
antibody
gene rearrangement of antibodies occurs where?
the bone marrow
somatic hypermutation and isotype switching occurs where?
secondary lymphoid organs and circulation
antibody genes are assembled from ___
fragmented segments
which chromosomes are the lambda light chain loci, kappa light chain loci, and heavy chain loci on?
- lambda light chain - chromosome 22
- kappa light chain - chromosome 2
- heavy chain - chromosome 14
antibody production requries ___
recombination
this produces enormous diversity of antigen binding
what are the regions of genomes used to construct antibodies?
- kappa light chain
- variable, joining/junctional, and constant/conserved
- lambda light chain
- variable, joining/junctional, and constant/conserved
- heavy chain
- variable, diversity, joining/junctional, and constant/conserved
somatic recombination creates ___
antibody coding sequence
somatic recombination follows a ___ sequence, tied to specific ___
- set
- B cell developmental stages
in somatic recombination, segments are ___ paired
randomly
the ___ complex randomly pairs gene segments. the gene segments are randomly paired to create ___.
- RAG
- coding sequences
junctional diversity is created during ___
recombination
every time you pair a variable, diversity, or junctional region, you add ___ to that sequence. which enzyme facilitates this?
- additional nucleotides
- TdT - terminal deoxynucleotidyl transferase
a single B cell can express all ___
antibody isotypes
B cells usually only express one antibody, except in which case?
somatic hypermutation rapidly increases ___
antibody affinity
antibodies are important ___ and ___ tools
diagnostic and therapeutic
what does polyclonal refer to?
multiple antibodies targeted against the same antigen
what does monoclonal refer to?
a single antibody targeted against a single antigen
describe how antibodies are important diagnostic and therapeutic tools
- diagnostic
- pathogen identification
- protein quantification
- cellular identification
- therapeutic
- targeted killing
- chemical delivery
- immunomodulatory
