Unit 3 Serology Flashcards
What are three methods of identification of micro organisms
Direct microscopic evaluation, cultivation and biochemical tests, Serological test
What is serology
Tests based on the interactions of antibodies and antigens. Theyre developed to determine the presence of antibodies or antigens in a patient
What is sensitivity
The ability to recognize an bind to antigens
What is specificity
Characteristic of binding only to one antigen and not to others
What are the principles of serological reactions
Based on the formation of antibody antigen complexes. If antibodies are found in the serum of an animal it demonstrates that the animal has had contact with the specific antigen
What is an antibody tighter test
Measurement of how much antibody an organism has produced that recognizes a particular epitope
What is the concentration of antibodies in the serum considered
The antibody tighter
How is antibody tighter expressed
Expressed is the inverse of the greatest dilution that still gives a positive result
What is the function of single serum testing
Used to check immune status and does not always give enough information for diagnosis
Why can false negatives occur in single serum testing
Due to the fact that the anti-bodies may not have formed yet if a disease is in early stages
What is the definition of paired sera
Two serum samples taken at least two weeks apart with the first being taken during the acute phase and the second being taken during convalescence
How is paired serum processed
Both must be tested in parallel to ensure consistency of testing. Hold and freeze acute sample until convalescent samples collected and both are sent together to the lab
What are considered significant results in paired serum testing
Fourfold or greater increase between acute and convalescence
What are hybridomas
Produced by the fusion of malignant and plasma cells. The resulting population of cells is immortal and able to produce large amounts of a specific antibody
What are the advantages to hybridomas
They are uniform, highly specific and can be produced in large quantities
What are the uses of hybridomas
Serological identification, prevention of tissue rejection, cancer research.
Describe when precipitation reactions occur between antigens and antibodies
Precipitation reactions occur only when the ratio of antigen and antibody’s are off tomorrow. Optimal ratio is produced when separate solutions of antigen and antibody’s are placed adjacent to each other and allowed to diffuse together
What is the ouchterlony test
Both antigen antibody is defuse radio leaf ramose toward each other, thereby establishing a concentration gradient. As equivalents is reached a visible line of precipitation forms. Determines the relationship between antigens and the number of different antigen antibody complexes present
What is a coggins test
Sensitive diagnostic test for equine infectious anemia
What is immunoelectrophoresis
Combines electrophoresis with immunodiffusion for the analysis of serum proteins. Antigens are placed in a well on an agar coated slide and an electric current is passed to the gel. The antigens migrate at different rates through the gel depending on their size and electric charge. One separation has completed, the anti-body is placed in the trough that is been made in the gel and diffusion will occur. The precipitate will form
What is agglutination
Androgens linked together by antibodies to form visible aggregates. Can be direct or indirect
What is direct agglutination
Direct agglutination reactions test patient serum for the presence of antibodies against ️large cellular antigens. They can be used to determine antibody titre
What is a pathognomonic diseases
A disease with a very specific clinical sign that does not require any testing.
What is a hemagglutination reaction
What agglutination reactions involve clumping red blood cells. They are used in blood typing, diagnosis of certain disease, identification of viruses
What is indirect agglutination
Testing patient’s serum for the presence of antibodies against soluble antigens. Serum is mixed with latex spheres with the soluble antigens attached. Anti-bodies within cause visible agglutination of latex spheres with the soluable antigens
What is an ELISA test
Enzyme linked immuno absorbent assay.
What does the indirect Eliza test detect
Anti-bodies
What does the direct Eliza test detect
Antigens
Describe the direct Elisa test
Used to detect specific antigens against a antibody bound in the test chamber. Used when you want to know if a patient sample contains a specific antigen. Chamber coated with anti-bodies, antigens are added, chamber added antibodies.
How do you know if you have a positive direct Eliza test
If an enzyme linked anti-body is present, a product will be formed and cause a color change
What is an indirect Eliza test
It is used when you want to know if a patient sample contains an antibody against a specific antigen. coat chamber with antigen. Add antibodies. Add enzyme linked antibodies.
How do you know if you have a positive indirect Eliza test
Add substrate and look for a color change
What are the two types of in clinic Eliza tests
Immunofiltration and immuno chromatography
Describe an immunofiltration Eliza test
Appearance of colored dots in the absorbent bed indicates a positive test
Describe an immunochromatography Eliza test
Antigen is allowed to flow through a porous strip, until it meets the conjugate. It then meets some antibodies and a coloured line will appear if it is specific for these antibodies.
What are some important idexx snap tests
4Dx,
Fiv/felv
Cpl
Parvo
What is radioimmunoassay
Used to measure concentration of antigens by using antibodies. You make a known quantity of antigens radioactive. Then mix with a known amount of antibodies. Then mix sample of Serum. Then measure radioactivity levels using a gamma counter
What is a western blot
Used to identify antigens in a patient sample. Separate proteins in patient sample by electrophoresis and transfer to a filter membrane,. If specific antigen is present in the sample the antibodies will combine with it and be visible as a colored band.
What is a PCR test
Polymerase chain reaction test. Used to amplify a single copy of a piece of DNA to generate thousands of millions of copies. Requires very small amounts of DNA sample
Briefly describe a PCR test
Using thermal cycling, consisting of cycles of repeated healing and cooling. Primers containing sequences complementary to the target region along with a DNA polymerase are key components to enable selective and repeated amplification. As PCR progresses the DNA generated is itself used as a template for replication
What is needed for a polymerase chain reaction
Heat resistant DNA polymerase enzymes. DNA primers. Test samples. DNA nucleotides
What is immunofluorescence
Using fluorescent antibody used to visualize specific antigens. Direct or indirect fluorescent antibody test
What is the purpose of immunofluorescence
To detect a location an abundance of proteins for what you have an antibody. Use of fluorescent dye that is attached to an antibody
What is direct immunofluorescence
Uses a primary antibody linked to a flurophore. The primary antibody recognizes the target antigen and binds to it. The attached flurophore can be detected by a fluorescent microscopic
What is indirect immuno florescence
Uses two antibodies. The unlabeled first antibody specifically binds the target molecule. The second antibody which carries the flurophore recognizes the primary antibody and binds to it
