What is immunodiagnosis
detection of antibodies can help provide definitive diagnosis
What is serology
refers to the use of serum antibodies to detect and measure antigens or conversely the use of antigens to detect serum antibodies
What is Titer
amount of antibody is the titer
- as infection progresses more antibodies are formed and the amound of antibody in the blood increases
- small but steady amounts of antibody could result from infection at a previous time giving important information regarding persons current immunity
- a rise in titer is characteristic of active infection
What is serotype
a strain that has a characteristic antigenic structure that differs from other strains
-serotype determination is critical for tracking transmission and emergence of infections
What is ELISA
Enzyme-Linked ImmunoSorbent Assay
-uses two antibodies, one of which is specific to the antigen and the other of which is coupled to an enzyme
What is agglutination
the interaction between antibody and antigen results in cross linking and lattice formation
What is precipitation
the interaction between antibody and a soluble antigen in aqueous solution forms a lattice that develops into a visible precipitate
What is immunodiffusion
immune precipitates also form in agar. As antibody and antigen diffuse toward one another a visible line will form
What is complement fixation
older test not used much today
- indicator system is red blood cells from sheep
- the presence of of hemolysins and complement the RBCs will lyse
What is capsular swelling
quellung reaction
- swelling of the capsule surrounding a microorganism after reaction with an antibody
- typically used for strep
What are neutralization tests
- specific antibodies present will neutralize effect of toxin
- not used much today
What is immunofluorescence
-fluorescent dyes can be attached to known specific antibodies which are then used to detect the presence of an antigen in serum
What is the schick test
intracutaneous skin test enables to distinguish between individuals who are susceptible and those who are resistant to diptheria toxin
What is the tuberculin skin test
- not an antibody mediated test
- this is a cell mediated response, specifically
- people who have been exposed to TB will develop immune response causing slight swelling at injection site
