Erythrocyte agglutination test

Blood typing is one common application of the agglutination test.10 Human erythrocytes may possess either or both of epitopes A and B on their surfaces. Individuals possessing only epitope A have Anti-B in their serum, while individuals possessing only epitope B on their erythrocytes have circulating Anti-A. Some individuals have neither epitope, and both antibodies present, while others have both epitopes, and neither antibody. Table 5.2 lists the four major blood groupings, and the epitopes and antibodies present in their serum. 

Figure 11.30 Adjuvant effect of nano-encapsulated human immunogammaglobulin-G (IgG). Antigens with various adjuvants and untreated. Immunization of guinea-pigs after subcutaneous application of IgG. Antibody formation against IgG measured with a passive agglutination test (haemagglutination microtechnique) from guinea-pig serum with antigen-sensibilized sheep erythrocytes. The adjuvant effect of nano-encapsulated IgG compared to a classical Al203lgG adsorbate is evident. From Speiser [186].

Finally, the clusters were tested as inhibitors of hemagglutination of pig and rabbit erythrocytes by type-1 piliated UTI89 clinical isolate E. coli. The inhibition titer (IT), that is, the lowest concentration of the inhibitor at which no agglutination occurs, showed tetramer 51 to be the best inhibitor of hemagglutination, with an IT of about 3 fiM, or a factor of 6000 as compared to its affinity, and corresponding to 1000-fold better inhibition than that induced by D-mannose. Overall, tetravalent cluster 51 was the best noncovalent cross-linker of Con A and the best ligand known to E. coli K12 FimH. 

If blood from blood group A is transfused into the circulation of an individual with blood group B, for example, then the anti-A present there binds to the A antigens. The donor erythrocytes marked in this way are recognized and destroyed by the complement system (see p. 298). In the test tube, agglutination of the erythrocytes can be observed when donor and recipient blood are incompatible. 

Agglutinating reagent Erythrocytes tested 1 8 Titer agglutinating reagent mixed with equal volume of ... 

One standard test for RF uses polystyrene latex particles coated with human IgG. The relative concentration of RF in an unknown serum is estimated from the maximum dilution at which it is still capable of aggregating the coated particles. Alternatively, rheumatoid factor can be estimated through its ability to agglutinate sheep erythrocytes sensitized with a subagglutinating dose of rabbit antisheep erythrocyte antibody. A variety of related procedures has been utilized in various laboratories. 

Direct agglutination reactions which are used in blood banking to test for erythrocyte blood group surface antigens. Specific blood group antisera are used. 

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