PH 310 Exam Questions With
Verified Answers
4 attributes of adaptive immunity - ANSWER 1) specificity
2) memory: remembers, next response quicker
3) amplification: clonal expansion
4) modulation: switching of ab isotypes
primary and secondary response in adaptive immunity - ANSWER primary: lag phase is
1 week, ab number peaks for a few days, then rapidly decreases (predom IgM)
secondary: no lag phase, bigger response/many ab made, response remains high for a
few days (predom IgG and a lil IgM)
third response even stronger
antibody (BCR) basic structure - ANSWER - 4 polypeptide chains: 2 heavy H (50 kDa), 2
light L (25 kDa)
- linked by disulfide bonds
- variable region at N-terminus
- constant regions has c-terminus
Ig are membrane bound form and antibodies are the secreted form --> when bound by
antigens, B-cells differentiates to antibody-secreting plasma cells - ANSWER
plant protease papain cleaves ab into - ANSWER - 2 Fab fragments [fragment antigen
binding] that can still bind antigen
- 1 Fc fragment [fragment crystallizable] that can still opsonize
gut protease pepsin does____ - ANSWER degrades Fc from F(ab)2 fragment --> learned
that Fc on intact ab is important for opsonization
immunoglobulin isotype aka class of antibody - ANSWER genetic variations in the
CONSTANT REGIONS of heavy and light chains; GAMED; variable regions are the same
heavy chain isotypes - ANSWER alpha (IgA), delta (IgD), epsilon (IgE), gamma (IgG), mu
(IgM)
,light chain isotypes - ANSWER kappa and lambda
paratope - ANSWER ag-binding site on the ab; 4 framework regions (FR) have little
variability, 3 hypervariable regions (HV) aka complementary determining regions (CDR)
provide a binding surface for ag
ab tertiary structure - ANSWER constant domains have few loops, variable domains
have many fingerlike loops that can bind ag at antigen binding site
epitopes - ANSWER antigenic region on ag where ab binds; carbohydrates, proteins, or
both; most ag are multivalent
type of bonding of ag-ab - ANSWER weak non-covalent; lock and key model where there
is a complementarity of shape, charge, polarity, hydrophobicity
epitopes bind to - ANSWER pockets, grooves, surfaces
post-translational events - ANSWER - polypeptide glycosylation influences ab-ag
interactions
- proteins for secretion vs insertion into phospholipid bilayer and then presented cell
membrane
immunoglobulin diversity - ANSWER - Ig genes are fragmented in all cells so that they
cannot be expressed EXCEPT for in the B-cell
- consist of gene loci
- called the germline configuration
Recombination activating genes (RAG) enzymes 1 and 2 - ANSWER found only in
lymphocytes in b and t cells and no other body cells
gene segment recombination - ANSWER - Ig constant region genes are ready to
transcribe and don't need to be spliced (but still consist of introns and exons)
- ig variable region genes are coded by V, J, or D gene loci that require RAG-mediated
rearrangement
- the 3rd HV region is coded by a spliced junction between VJ or VDJ, which increases
variable domain diversity
light chain has one recombo event and heavy chain has two (to join DJ and then VDJ) -
ANSWER
Recombination Signal Sequences (RSS) - ANSWER - directs RAG mediated gene
segment recombination
- two types of RSS: heptamer and nonamer
- 12 or 23 bp separate the 7 and 9
,- gene to be cut is always flanked by 7, RAG binds at 12/23 bp sequences and cuts the
heptamer
- gene segments that will join are always flagged by heptamer (cut site)
from igM and igD to the others - ANSWER - naive B-cells express IgM and IgD
- VDJ rearranging triggers tx of full Ig gene, the mRNA is spliced, then translated
- igM and igD heavy chain C regions are transcribed and expressed first REVERSIBLE
PROCESS
allelic exclusion - ANSWER each B-cell produces Ig of only one specificity: once variable
region is rearranged, it is PERMANENT and cannot longer be altered
- ANSWER 1) gene segment recombination
2) allellic exclusion
how Ig goes to the surface - ANSWER - Ig polypeptides enter ER to assemble into Ig
molecules
- hydrophobic *membrane coding (MC)* region if present inserts into membrane
REVERSIBLE PROCESS
- Ig then associates with IgB and IgA transmembrane proteins linked by disulfide bonds,
and these serve to signal the B-cell that has surface Ig
B cell receptor (BCR) - ANSWER surface Ig on a B cell that binds to a specific antigen.
affinity maturation - ANSWER ag bound to ab causes structural changes in the Ig,
attracts IgA and IgB transmembrane proteins, which signals the b-cell to rapidly divide.
will IRREVERSIBLY hypermutate and increases diversity of rearranged gene segments.
over time, ab becomes more specific for the ag
ab isotype switching - ANSWER 1) IgM and IgD are co-expressed on B-cells. IgM
secreted first as a pentamer bc it is transcribed first
3) isotype switching is IRREVERSIBLE DNA recomb that rearranges the same V-region
with other heavy-chain constant genes (loops out)
4) switch to IgG is common.
5) V region is the same for all isotypes but C-regions determine effector functions
IgM secreted form - ANSWER pentamer linked by a J chain
IgD secreted form - ANSWER monomer
IgG secreted form - ANSWER monomer
, IgE secreted form - ANSWER monomer
IgA secreted form - ANSWER dimer linked by J chain. Most common secreted ab in
mucus membranes (guts, eyes) bc J chain can go through the epithelium
heaviest Ig - ANSWER IgM
most common Ig in serum - ANSWER IgG bc it is small and can distribute better
longest half life Ig - ANSWER IgG
shortest half life Ig - ANSWER IgE and few in serum
fewest Ig in serum - ANSWER IgE bc only for allergies
IgM is good at - ANSWER - neutralization
- activation of complement sys
- transport across epithelium
IgD is good at - ANSWER nothing
IgG is good at - ANSWER - neutralization
- opsonization
- some sensitization for killing by NK cells
- some sensitization of mast cells
- activation of complement system
- transport across placenta
- diffusion into extravascular sites
IgA is good at - ANSWER - neutralization
- opsonization
- activation of complement sys
- transport across epithelium
- diffusion into extravascular sites
IgE is good at - ANSWER - sensitization of mast cells
- diffusion into extravascular sites
immunoassay - ANSWER a sensitive analytical test that utilizes highly specific ab-ag
complexes to produce a signal that can be measured and related to concentration of a
Verified Answers
4 attributes of adaptive immunity - ANSWER 1) specificity
2) memory: remembers, next response quicker
3) amplification: clonal expansion
4) modulation: switching of ab isotypes
primary and secondary response in adaptive immunity - ANSWER primary: lag phase is
1 week, ab number peaks for a few days, then rapidly decreases (predom IgM)
secondary: no lag phase, bigger response/many ab made, response remains high for a
few days (predom IgG and a lil IgM)
third response even stronger
antibody (BCR) basic structure - ANSWER - 4 polypeptide chains: 2 heavy H (50 kDa), 2
light L (25 kDa)
- linked by disulfide bonds
- variable region at N-terminus
- constant regions has c-terminus
Ig are membrane bound form and antibodies are the secreted form --> when bound by
antigens, B-cells differentiates to antibody-secreting plasma cells - ANSWER
plant protease papain cleaves ab into - ANSWER - 2 Fab fragments [fragment antigen
binding] that can still bind antigen
- 1 Fc fragment [fragment crystallizable] that can still opsonize
gut protease pepsin does____ - ANSWER degrades Fc from F(ab)2 fragment --> learned
that Fc on intact ab is important for opsonization
immunoglobulin isotype aka class of antibody - ANSWER genetic variations in the
CONSTANT REGIONS of heavy and light chains; GAMED; variable regions are the same
heavy chain isotypes - ANSWER alpha (IgA), delta (IgD), epsilon (IgE), gamma (IgG), mu
(IgM)
,light chain isotypes - ANSWER kappa and lambda
paratope - ANSWER ag-binding site on the ab; 4 framework regions (FR) have little
variability, 3 hypervariable regions (HV) aka complementary determining regions (CDR)
provide a binding surface for ag
ab tertiary structure - ANSWER constant domains have few loops, variable domains
have many fingerlike loops that can bind ag at antigen binding site
epitopes - ANSWER antigenic region on ag where ab binds; carbohydrates, proteins, or
both; most ag are multivalent
type of bonding of ag-ab - ANSWER weak non-covalent; lock and key model where there
is a complementarity of shape, charge, polarity, hydrophobicity
epitopes bind to - ANSWER pockets, grooves, surfaces
post-translational events - ANSWER - polypeptide glycosylation influences ab-ag
interactions
- proteins for secretion vs insertion into phospholipid bilayer and then presented cell
membrane
immunoglobulin diversity - ANSWER - Ig genes are fragmented in all cells so that they
cannot be expressed EXCEPT for in the B-cell
- consist of gene loci
- called the germline configuration
Recombination activating genes (RAG) enzymes 1 and 2 - ANSWER found only in
lymphocytes in b and t cells and no other body cells
gene segment recombination - ANSWER - Ig constant region genes are ready to
transcribe and don't need to be spliced (but still consist of introns and exons)
- ig variable region genes are coded by V, J, or D gene loci that require RAG-mediated
rearrangement
- the 3rd HV region is coded by a spliced junction between VJ or VDJ, which increases
variable domain diversity
light chain has one recombo event and heavy chain has two (to join DJ and then VDJ) -
ANSWER
Recombination Signal Sequences (RSS) - ANSWER - directs RAG mediated gene
segment recombination
- two types of RSS: heptamer and nonamer
- 12 or 23 bp separate the 7 and 9
,- gene to be cut is always flanked by 7, RAG binds at 12/23 bp sequences and cuts the
heptamer
- gene segments that will join are always flagged by heptamer (cut site)
from igM and igD to the others - ANSWER - naive B-cells express IgM and IgD
- VDJ rearranging triggers tx of full Ig gene, the mRNA is spliced, then translated
- igM and igD heavy chain C regions are transcribed and expressed first REVERSIBLE
PROCESS
allelic exclusion - ANSWER each B-cell produces Ig of only one specificity: once variable
region is rearranged, it is PERMANENT and cannot longer be altered
- ANSWER 1) gene segment recombination
2) allellic exclusion
how Ig goes to the surface - ANSWER - Ig polypeptides enter ER to assemble into Ig
molecules
- hydrophobic *membrane coding (MC)* region if present inserts into membrane
REVERSIBLE PROCESS
- Ig then associates with IgB and IgA transmembrane proteins linked by disulfide bonds,
and these serve to signal the B-cell that has surface Ig
B cell receptor (BCR) - ANSWER surface Ig on a B cell that binds to a specific antigen.
affinity maturation - ANSWER ag bound to ab causes structural changes in the Ig,
attracts IgA and IgB transmembrane proteins, which signals the b-cell to rapidly divide.
will IRREVERSIBLY hypermutate and increases diversity of rearranged gene segments.
over time, ab becomes more specific for the ag
ab isotype switching - ANSWER 1) IgM and IgD are co-expressed on B-cells. IgM
secreted first as a pentamer bc it is transcribed first
3) isotype switching is IRREVERSIBLE DNA recomb that rearranges the same V-region
with other heavy-chain constant genes (loops out)
4) switch to IgG is common.
5) V region is the same for all isotypes but C-regions determine effector functions
IgM secreted form - ANSWER pentamer linked by a J chain
IgD secreted form - ANSWER monomer
IgG secreted form - ANSWER monomer
, IgE secreted form - ANSWER monomer
IgA secreted form - ANSWER dimer linked by J chain. Most common secreted ab in
mucus membranes (guts, eyes) bc J chain can go through the epithelium
heaviest Ig - ANSWER IgM
most common Ig in serum - ANSWER IgG bc it is small and can distribute better
longest half life Ig - ANSWER IgG
shortest half life Ig - ANSWER IgE and few in serum
fewest Ig in serum - ANSWER IgE bc only for allergies
IgM is good at - ANSWER - neutralization
- activation of complement sys
- transport across epithelium
IgD is good at - ANSWER nothing
IgG is good at - ANSWER - neutralization
- opsonization
- some sensitization for killing by NK cells
- some sensitization of mast cells
- activation of complement system
- transport across placenta
- diffusion into extravascular sites
IgA is good at - ANSWER - neutralization
- opsonization
- activation of complement sys
- transport across epithelium
- diffusion into extravascular sites
IgE is good at - ANSWER - sensitization of mast cells
- diffusion into extravascular sites
immunoassay - ANSWER a sensitive analytical test that utilizes highly specific ab-ag
complexes to produce a signal that can be measured and related to concentration of a
