Exam 2 Flashcards
Detergents may be added to wash buffer
Reduce hydrophobic interactions
Frozen sections may be preferred in immunohistochemistry if the antigen
Susceptible to heat
Intrinsic affinity determined by the
Idiotype
Which is true of immunohistochemistry
It can be used to determine the origin of tumors
Blocking endogenous biotin is necessary when using
Streptavidin detection system
Paraffin sections for IHC should be sectioned between
3-4 um
Polyclonal antibodies are generated through
Immunogen boosters and serum purification
When used as blocking reagent, 1% BSA
Bind to the non specific protein in tissue to prevent background
The clone of an antibody is determined by the
Idiotype
The method of antigen retrieval most dependent on
Fixation
Non-specific staining due to Fc receptor in tissues is more of a concern with
Frozen sections
Frozen sections for immunohistochemistry most commonly fixed in
Acetone
Maximum recommended temperature that tissue for IHC should be exposed to during processing
60-65
Underdigestion w enzyme retrieval will most likely cause
False negatives
Hybridoma is produced when B lymphocytes are fused with
Myeloma tumor cells
Following enzyme retrieval, the tissue is fragmented and lifting off the slide
Enzyme digestion step was too long
One purpose of epitope retrieval is to
Restore tertiary structure
Chemical used to quench endogenous alkaline phospatase in tissue sections
Levamisole
Blocking endogenous enzymes is necessary to prevent
Non specific staining
Fixatives that tend to mask antigenicsites through crosslinking and hamper detection by antibodies contain
Aldehydes
Which of the following may serve as a Wash buffer and HIER solution
Tbs
Advantage of lHC over molecular techniques
Tumor heterogeneity can be detected
Tris buffer
As temp increases pH decreases
Purpose of wash buffer
Avoid non specific staining
When selecting a primary antibody, the reactivity species is defined as the
Species the antigen is within
Antibody class most frequently used in IHC is
IgG
Molecule that specifically binds with antibody is referred to as
Antigen
Immunoglobulin light chain class
Kappa
Portion of immunoglobulin determining idiotype
Variable domain
Cold ischemic time
Tissue removal from patient to placement in fixative
Fixative not recommended due to inconsistent staining results
Bouins
Endogenous biotin most prevalent in
Liver
IgG immunoglobulin has how many binding sites
2
Antigen diffusion
Unexpected displacement of antigens from their normal location
What tissue is susceptible to background staining due to hydrophobic interactions
Connective tissue
High background/nonspecific staining is seen in IHC stained tissue section.Which protocol step was omitted
Blocking
The antigen binding site of an antibody may also be referred to as the
Paratope
The most commonly recommended incubation temperature for EIER
37
The most aggressive HIER
Pressure cooker
What is an advantage of epitope retrieval
Decreases background staining
The purpose of fixation in IHC is to preserve morphology and
Immobilize the antigen
What fixative for paraffin embedded tissues may decrease the need for antigen retrieval
Zinc formalin
Monoclonal antibodies produced in this species are considered
Rabbit
Which portion of the immunoglobulin is composed only of heavy chain
Fc
With increased antibody affinity, the concentration of the antibody
Can be decreased
The term for an antibody reacting with an epitope that is not the target epitope
Cross reactivity
When selecting a primary antibody the host species must be
Different than the reactivity species
Distilled water should be used to prepare wash buffers to prevent
Contamination
Reprocessing of tissue is not recommended in immunohistochemistry because
Irreversible epitope damage may occur
Which of the following is the preservative used in buffer solution
Sodium azide
A homogeneous immunoglobulin that result from the proliferation of a single plasma cell line is defined as
Clone
IHC stained sections show optimal positive staining at the edges of the tissue and absent staining in the middle
Under fixation
Reduces hydrophobic interactions
Triton x
Which antibody would be more susceptible to cross reactivity
Polyclonal
The pH of the HIER solution is dependent on the
Target antigen and affinity of the antibody
Digestion with pepsin
F(ab1)2
Contain a spectrum of low to high affinity antibodies
Polyclonal antibody
What wash buffer has more potential for background staining
Phosphate based
This component of an immunoglobulin is either kappa or lambda
Light chain
Equilibrium is reached when
All available epitopes are bound with antibody
On formalin fixed paraffin embedded tissue sections that have been deparaffinized what is the next step
Antigen retrieval
Papain digestion cleaves the IgG molecule into
Two monovalent antigen-binding fragments
The portion of the antigen to which the antibody is attracted
Epitope
In horseradish peroxidase methods a solution of 3% hydrogen peroxide alone is used to
Block endogenous peroxidase
Most gentle HIER method on tissue sections
Waterbath
In reference to the IgG structure, F(ab1)2 is composed of
One bivalve the fragment
Underfixation can result in
Antigen diffusion
The ideal fixation time for immunohistochemistry is
24-72 hours
In which of the following instances would you most likely encounter cross species reactivity
A mouse anti-human antibody detecting an antigen in rat tissue
Enzyme used for EIER
Protease
What is a function of a detergent/surfactant in IHC reagents
Solubilizes the cell membrane
Long term fixation results in
Decreased antigenicity
When using a wash buffer, what is not good practice
Combining old buffer w new buffer
Monoclonal antibodies are highly specific, however they may be susceptible to weak staining due to
Dependence on the presence of a specific epitope
