Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
CLT105 Ch8xxx
precipitation reactions
| Question | Answer |
|---|---|
| Combining soluble antigen with soluble antibody to produce insoluble complexes that are visible. | Precipitation |
| For such reactions to occur, both antigen and antibody must have multiple ________ sites for one another, and the relative ____________ of each must be equal. | binding sites; concentration |
| Binding characteristics of antibodies, called _______and _______, also play a major role. | affinity and avidity |
| ________is the initial force of attraction that exists between a single Fab site on an antibody molecule and a single epitope or determinant site on the corresponding antigen | Affinity |
| As epitope and binding site come into close proximity to each other, several types of __________ bonds hold them together. | noncovalent |
| ionic bonds, hydrogen bonds, hydrophobic bonds, and van der Waals forces are_____ | noncovalent bonds???? |
| The more the cross-reacting antigen resembles the original antigen, the ________ the bond will be between the antigen and the binding site. | stronger |
| if the epitope and the binding site have a perfect _____ relationship, as is the case with the original antigen, the affinity will be ________, because there is a very close fit | lock-and-key; maximal |
| ________ represents the sum of all the attractive forces between an antigen and an antibody | Avidity |
| Avidity involves the ______ with which a multivalent _____ binds a multivalent antigen, and it is a measure of the overall ________ of an antigen–antibody complex. | strength;antibody; stability |
| Avidity is the _______ that keeps the molecules together. | force |
| All antigen–antibody binding is reversible and is governed by the ______ | the Law of mass action |
| The _______ (K) represents the difference in the rates of the forward and reverse reactions of antigen and antibody association. | equilibrium constant |
| The equilibrium constant can be seen as a measure of the _________ between antigen and antibody. | goodness of fit |
| The higher the value of K, the ______ the amount of antigen–antibody complex and the __________ or easily detectable the reaction | larger;more visible |
| The ideal conditions in the clinical laboratory would be to have an antibody with a __________, or initial force of attraction, and a _______, or strength of binding. | high affinity; high avidity |
| The higher the values are for afinity and avidity and the more antigen–antibody complexes that are formed, the more ____________ the test will be. | sensitive |
| ________ depends on the relative proportions of antigen and antibody present. | precipitation |
| Optimum precipitation occurs in the zone of ________, in which the number of multivalent sites of antigen and antibody are approximately equal. | zone of equivalence |
| when increasing amounts of soluble antigen are added to fixed amounts of specific antibody, the amount of precipitation ____ up to the zone of equivalence. | increases |
| when the amount of antigen overwhelms the number of antibody combining sites present, ________ begins to decline. | precipitation |
| On the precipitation curve, precipitation declines on either side of the equivalence zone due to _______ | an excess of either antigen or antibody. |
| In the case of antibody excess, ______ occurs, in which antigen combines with only one or two antibody molecules, and no _______ are formed | the prozone phenomenon; cross-linkages |
| At the other side of the zone, where there is antigen excess, the _______ occurs, in which small aggregates are surrounded by excess antigen, and again no lattice network is formed. | postzone phenomenon; lattice |
| For precipitation reactions to be detectable, they must be run in the _________. | zone of equivalence |
| The prozone and postzone phenomena must be considered in the clinical setting, because _________ reactions occur in both. | negative |
| A false-negative reaction may take place in the prozone due to ______ concentration. | high antibody |
| If it is suspected that the reaction is a false negative, diluting out antibody and performing the test again may produce a ________ result. | positive |
| In the_______, excess antigen may obscure the presence of a small amount of antibody. Typically, such a test is repeated with an additional patient specimen taken about a _______ later. | postzone; week |
| Precipitates in fluids can be measured by means of ________ or __________. | nephelometry; turbidimetry |
| ________ is a measure of the turbidity or cloudiness of a solution. | Turbidimetry |
| ________ measures the light that is scattered at a particular angle from the incident beam as it passes through a suspension. | Nephelometry |
| Nephelometry can be used to detect either antigen or antibody, but it is usually run with antibody as the ________ and the patient antigen as the ________. | reagent; unknown |
| Nephelometry provides accurate and precise quantitation of ________, and due to automation, the cost per test is typically lower than other methods. | serum proteins |
| The precipitation of antigen–antibody complexes can also be determined in a support medium such as a ________. | gel |
| Reactants are added to the gel, and antigen–antibody combination occurs by means of ______. | diffusion |
| When no electrical current is used to speed up diffusion process, it is known as ________. | passive immunodiffusion. |
| The rate of diffusion is affected by the ________ of the particles, the _________, the gel ________, and the amount of hydration. | size; temperature; viscosity |
| It has been commonly used in the clinical laboratory; It is a technique where the antibody is uniformly distributed in the support gel, and antigen is applied to a well cut into the gel. | Radial immunodiffusion (RID) |
| (RID) As the antigen diffuses out from the well, antigen–antibody combination occurs in changing proportions until the zone of equivalence is reached and a ________ network is formed in the gel. | stable lattice |
| The area of the ring obtained in the well (RID) is a measure of _________, and this can be compared to a ________ obtained by using antigens of known concentration | antigen concentration; standard curve |
| There are two techniques for the measurement of radial immunodiffusion.The first was developed by Mancini and is known as the _________ method.The Fahey and McKelvey method, also called the ________ method | end-point; kinetic |
| In this technique, _____ is allowed to diffuse to completion, and when equivalence is reached, there is no further change in the ring diameter. | antigen ; ring diameter |
| The end-point method occurs between 24 and 72 hours.The square of the diameter is then _________ ______ to the concentration of the antigen. | directly proportional |
| The_________method, uses measurements taken before the point of equivalence is reached. In this case, the diameter is proportional to the _________. | kinetic; log of the concentration |
| One of the older, classic immunochemical techniques is ________ diffusion. | Ouchterlony double diffusion |
| In what technique, both antigen and antibody diffuse independently through a semisolid medium in two dimensions: horizontally and vertically. | Ouchterlony double diffusion (ODD) |
| During Ouchterlony double diffusion, Wells are cut in a _____, and _______ are added to the wells. | gel;reactants |
| Ouchterlony double diffusion--After an incubation period of between 12 and 48 hours in a _________ chamber, __________ form where the moving front of antigen meets that of antibody. | moist; precipitin lines |
| ODD---The density of the precipitin lines reflects the amount of ___ _______formed. | immune complex |
| Most Ouchterlony plates are set up with a central well surrounded by four to six ____________ wells. | equidistant outer wells |
| Multispecific antibody is placed in the _____ well, and different antigens are placed in the ______ wells to determine if the antigens share identical ________. | central; surrounding; epitopes |
| 1. Fusion of the lines at their junction to form an arc represents _________ identity, or the presence of a ________ epitope. | serological; common |
| 2. A pattern of crossed lines demonstrates two separate reactions and indicates that the compared antigens share _______ epitopes, or _________. | no common; nonidentity |
| 3. Fusion of two lines with a spur indicates ____________.The “spur” in the latter always points to the ___________. | partial identity; simpler antigen |
| Ouchterlony double diffusion is still used to identify __________ such as Aspergillus, Blastomyces, Coccidioides, and Candida. | fungal antigens |
| Diffusion can be combined with electrophoresis to speed up or sharpen the _________. | results |
| ___________ separates molecules according to differences in their electric charge when they are placed in an electric field. | Electrophoresis |
| One-dimension ____________, an adaptation of radial immunodiffusion, was developed by Laurell. | electroimmunodiffusion |
| Antibody is distributed in the gel, and antigen is placed in wells cut in the gel, just as in RID.__________ is used to facilitate migration of the antigen into the agar. | Electrophoresis |
| The end result is a precipitin line that is conical in shape, resembling a rocket, hence the name ___________.This technique has been used to ____ _________. | rocket immunoelectrophoresis; quantitate immunoglobulins |
| The_________ of the rocket, measured from the well to the apex, is directly in proportion to the amount of ________ in the sample | height;antigen |
| _________ is a double-diffusion technique that incorporates electrophoresis current to enhance results. | immunoelectrophoresis |
| Typically in immunoelectrophoresis, the source of the antigens is _______, which is electrophoresed to separate out the main __________ fractions. ________is placed in troughs, and the gel is incubated for 18 to 24 hours. | serum; protein; Antiserum |
| Precipitin lines develop where specific __________ combination takes place. | antigen–antibody |
| Precipitin lines or lines or arcs can be compared in shape, intensity, and location to that of a _______ control to detect ____________. | normal serum; abnormalities |
| Immunoelectrophoresis procedure has been used as a screening tool for the differentiation of many _________, including the major classes of immunoglobulins. | serum proteins |
| Immunofixation electrophoresis is similar to immunoelectrophoresis, except that after electrophoresis takes place, antiserum is applied directly to the _________ rather than placed in a trough. | gel’s surface |
| ________ form only where specific antigen–antibody combination has taken place, and the complexes have become trapped in the gel. | Immunoprecipitates |
| Patient serum is applied to __ lanes of the gel, and after electrophoresis, __ lanes are overlaid with one each of the following antibodies: antibody to gamma, alpha, or mu heavy chains and to kappa or lambda light chains. | six; five |
| The sixth lane is overlaid with antibody to _______ and serves as the reference lane. | all serum proteins |
| Hypogammaglobulinemias will exhibit faintly _______ bands, while polyclonal hypergammaglobulinemias show _____ staining bands in the ______ region. | staining bands; darkly; gamma |
| Monoclonal bands, such as found in __________ macroglobulinemia or multiple myeloma, have dark and narrow bands in specific lanes | Waldenström’s; myeloma |
| __________ is especially useful in demonstrating antigens present in serum, urine, or spinal fluid in low concentrations | Immunofixation |
| Perhaps one of the best-known adaptations of this technique is the ________, used as a confirmatory test to detect antibodies to HIV-1 | Western blot;HIV-1 |
| Western blot technique: A mixture of HIV _____ is placed on a gel and __________to separate the individual components.The components are then transferred to ___ paper. | antigens; electrophoresed; nitrocellulose |
| Patient serum is applied to the nitrocellulose and allowed to react by ______. | incubation |
| _______ is done by means of blotting or laying the nitrocellulose over the gel so that the electrophoresis pattern is preserved. | transfer of individual components |
| After the incubation--The strip is then washed and stained to detect_______ bands. Antibodies to several ______ can be detected in the patient sample . | precipitin; antigens |
| Concentration is directly in proportion to the square of the diameter | end-point method of RID |
| The diameter is proportional to the log of the concentration | RID-kinetic method |
| readings are taken before the equivalance | RiD-kinetic method |
| It indicated the ratio of incident light to transmited light | measure of turbidity |
| radial immunodifusion + electrophoresis= | rochet electrophoresis |
| Antiserum is directly applied to the gel instead of being placed in a trough | Immunofixation electrophoresis |
| an antibody screening test is false-negative in _____ | prozone |
| If Ag1 and Ag2 have crossed lines results____ | the 2 antigens are unrelated |
| Which technique represents a single-diffusion reaction? | Radial Immunodifusion (RID) |
| The equilibrium constant is related to strength of antigen-antibody binding | The law of mass action |
| Ab+Ag difuse in semisolid medium; used to detect fungal antigens | ODD |
| Lines do not cross between Ab and Ag (fusion of lines at junction) | serological identity |
| Lines cross between Ab and Ag | not identical; no common determinant |
| fusion of 2 lines with spur (simpler Ag) | partial identity |
| The diameter of the ring shows the concentration of the Ag | end-point RID |
| Reactants are added to the well; keeped for 12-48h in a most chamber | ODD |
| equal nr of Ab+Ag in a precipitation reaction is called_______ | optimum precipitation in zone of equivalance |
| high nr antibody + low nr. Ag= | prozone |
| high nr Ag + low nr.antibody | postzone |
| colected during acute disease | acute serum specimen |
| collected after or during recovery | covalescent serum specimen |
| End point reactions are direct: ex:_______ and indirect in the lab (Ag +Ab= pos or neg rxn) | throat culture for strep infection |
| Concentration of Ab + Ag need to be equal so the rxn be________ | visible |
| diameter of ring is proportional with the concentration of Ag | RID |
| _ reacts optimaly at 22C | IgM |
| ____reacts optimally at 37C | IgG |
| enhances some Ag-Ab rxn by putting them in close proximity to one another | centrifugation |
| If incubation time is short= | rxn may be weak |
| If incubation time is long= | rxn may be variable |
| lock anf fit key | affinity |
| All avidity forces:__ | strength, stability, irreversable |
| goodness of fit | law of Mass Action |
| results in formation of large immune complexes | serum sickness |
| Ab reacts with unrelated epitope of Ag | cross reactivity (ex momonucleosis) |
| Ab +Ag diffuse toward each other in agar gel | Ouchterlony Double diffusion |
| double diffudion + electrophoresis to speed up rxn | imunoelectroporesis |
| immunodiffusion occures more _______ | rapidely |
| immunofixation electroporessis ex: | Western plot |
Created by:
tatianat