Exam 4: Dr. Sullivant Immunological Techniques Flashcards
What are the different diagnostic tests?
Primary binding tests* Secondary binding tests Tertiary binding tests Measuring antibody levels with titers* Molecular diagnostics*
What are primary binding tests?
Directly detects antigen binding to antibody
In primary binding tests, one of the reactants (Ab or Ag) must be chemically labelled for detection. What are those labels?
Radioisotopes
Fluorescent dyes
Enzymes
What are examples of primary binding immunoassays?
Immunofluorescence assays (IFA) Immunoenzymes assays
What are immunofluorescence assays?
Direct or indirect fluorescent antibody tests
What are immunoenzymes assays?
Enzyme-linked immunosorbent assays (ELISA)
Western blot
Immunohistochemistry
What does the direct fluorescent antibody of IFAs do?
Detects specific Ag in patient sample
What does the indirect fluorescent antibody of IFAs do?
Detects patient antibody to specific Ag
What is bound antibody detected with in indirect fluorescent antibody of IFAs?
FITC-labeled antiglobulin
What makes an ELISA test enzyme-linked?
An enzyme is conjugated to an antibody
What happens to the enzyme in ELISA?
It changes color when mixed with a substrate
What can ELISA detect?
Patient antibodies or antigens
What does the SNAP test detect for heartworms?
Antigen
What does the SNAP test detect for FeLV?
Antigen
Detects circulating FeLV virus
What does the SNAP test detect for FIV?
Antibody
Positive with infection or vaccination
What does the SNAP test detect for parvo?
Antigen
What does the SNAP test detect for lyme, anaplasma, and ehrlichia?
Antibodies
What does the SNAP test detect for leptospirosis?
Antibodies
What is the clinical use of western blot?
Conformation of other test results
Rile out false positives (i.e. vaccination)
What is the importance of enzymes with immunohistochemistry?
They are used as the label
They are conjugated with Ab or antiglobulin to locate specific antigen in tissue
What is the clinal case of IHC?
Diagnosis of disease and determination of tissue type in tumors
Actin Ab used to determine if skeletal muscles is in origin
Describe radioimmunoassays
Expensive
Clinical use: detection of trace drugs
What is antibody titration?
Testing for the amount of circulating antibodies present in the serum to a given pathogen
What does a high titer mean?
High concentration of antibodies
What does serum neutralization do (secondary binding)?
Incubate different concentrations of serum with virus
What is titer of microscopic agglutination tests?
The highest dilution that causes agglutination of 50% of the organisms
What does a positive PCR mean?
Target DNA found in patient sample
What is immunophenotyping useful for?
Assessing leukocyte populations
