Paul bunnel reaction is a ty pe of -
Ans. is 'a' i.e., Agglutination test Precipitationo When a soluble antigen combines with its antibody in the presence of electrolytes (NaCI) at a suitable temperature and pH, the antigen - antibody complex forms an insoluble precipitate,o When instead of sedimenting, the precipitate remains suspended as floccules, the reaction is knowm as flocculation.o It is very sensitive in detection of antigens and as little as 1 g of protein can be detected by precipitation tests,o Precipitation is relatively less sensitive for the detection of antibodies.Precipitation / flocculation testsRing testslide testTube testImmunodiffusionElectroimmuno- (Precipitation in gel)diffusion o Ascoli's thermo-o VDRLo Kahn testo Elek test foro Most important isprecipitation(flocculation test)(flocculation testtoxigenicity incountercurrenttest forfor syphilisfor syphilis)diphtheria bacilliimmunoelectrophoresisBacillus anthraxfor detection of alpha- o Grouping offetoprotein in serum streptococci byand cryptococcai the lancefieldantigen in the C.S.F. technique Agglutinationo When a particulate antigen is mixed with its antibody in the presence of electrolytes at a suitable temperature and pH, the particles are clumped or agglutinated,o Agglutination is more sensitive than precipitation for the detection of antibodies.Complement fixation testo The ability of antigen antibody complexes to 'fix' complement is made use of in the complement fixation test,o This is very sensitive test, capable of detecting 0.04 mg of antibody nitrogen and 0. i mg of antigen,o The source of complement is guinea pig serumo Exampleso Wassermann CFT for syphiliso Treponema pallidum immobilization test.Antigen - antibody reactionSoluble antigenParticulate antigenAntigen+++AntibodyAntibodyAntibody+++ElectrolyteElectrolyteSource of complement|||PrecipitationAgglutinationComplement fixation test
Agglutination
CF
Precipitation
Flocculation test
Antigen-antibody reaction