Serology Flashcards
What is a serological test?
A test based on the reaction between antigen and antibody
What is serology?
The study of the components of the blood, mainly antibodies
What are the diagnostic uses of serological tests?
Find antibodies in serum generated in response to pathogens
Detect presence of antigens
Identify blood groups
What are the research uses of serology?
Using antibodies to purify substances
What are the 3 antibody characteristics?
Affinity
Avidity
Specificity
What is affinity?
Strength of binding of ONE Fab region to the antigen
What is avidity?
Number of binding sites x affinity constant (Ka)
What are the two types of immunoassays?
Precipitation reactions
Agglutination reactions
What are precipitation reactions?
Formation of insoluble visible aggregates of antibodies and soluble antigens
What are agglutination reactions?
Formation of visible clumps due to binding of antibodies to large particles or cells
What are the three types of labelled immunoassays?
RIA and ELISA
Western blotting
Flow cytometry
What are RIA and ELISA?
Detection and quantification of antibody or antigen in aqueous solution
What is western blotting?
Detection and quantification of antigens in semi solid medium
What is flow cytometry?
Detection and analysis of individual labelled cells
What are radial immunodiffusion used to determine?
Relative concentrations of antibody or antigen
Compare antigens
Determine the relative purity of an antigen
What are hemaglutination reactions used for?
Blood group typing
Detect titer of viruses
What are bacterial agglutination reactions used for?
Measure antibody titer in serum
Direct identification of bacteria
Identify bacteria via specific antibodies in serum
What are the uses of latex agglutination?
Identification based on antibodies in serum
Rapid method
What is the principle of RIA (radioimmunoassay)?
Antigen-antibody reaction in which radio labelled antigens compete with endogenous antigen for limited binding sites
What is the application of RIAs?
Detect a variety of antigens, antibodies, hormones and drugs
What are the advantages and disadvantages of RIAs?
Adv: highly sensitive, fast, can be automated
Dis: uses radioactivity for detection
What is the purpose of ELISAs?
Very sensitive test for detection and quantification of antigens or antibodies in complex mixtures?
What is the basic principle of ELISA tests?
Uses antibodies labelled with enzymes to detect the present of a substrate
What are the main steps of an ELISA?
Coating/capture
Surface blocking
Probing/detection
Signal measurement
