Agglutination Reactions

The extent and speed of this agglutination depends on the hapten concentration in the plane of the membrane and on the lateral mobility of the hapten (G. K. H. Humphries, P. Brulet, H. McConnell, unpublished). It is extremely probable that this simple agglutination reaction leads to a change in the membrane shape. 

Agglutination reactions have many applications in clinical medicine that can be used to type blood cells for transfusion, to identify bacterial cultures, and to detect the presence and relative amount of specific antibody in a patient s serum. For example agglutination of antibody-coated latex beads has become a popular commercial method for the rapid diagnosis of various conditions such as pregnancy and streptococcal infections. 

The agglutination reaction is another type of precipitation reaction in which one of the components is present in a particulate form. The use of solid support like latex beads on which to coat a soluble antigen for an agglutination reaction with the corresponding antibody has greatly facilitated its ease of use. These assays are easy to perform however, they can give misleading results at low analyte concentration or interference from the sample matrix (48). 

S10. Sawai, M., Sudo, T., Okumura, H., Morita, S., Sato, S., Matsumoto, S., and Migita, S., A new photometric immunoassay of latex agglutination reaction with near infrared tur-... 

Interestingly, Matsumoto and Osawa196 reported that p-nitrophenyl (and phenyl) 2-acetamido-2-deoxy-/3-D-glucopyranoside, at a concentration of 10 mg/ml, did not inhibit the agglutination reaction between the potato lectin and human erythrocytes, whereas both p-nitrophenyl 2-acetamido-2,6-dideoxy-/3-D-gIucopyranoside and phenyl 2-acet-amido-3-0-(D-l-carboxyethyl)-2-deoxy-j3-D-glucopyranoside, at a level of 5 mg/ml, completely inhibited the hemagglutinin reaction. The... 

Precipitation reactions are similar in principle to agglutination reactions, the difference being that the antigen is a soluble, molecular species rather than a suspended particle such as a bacterium or erythrocyte. At a certain Ab/Ag ratio, the cross-linked polymeric network of antibody and antigen loses its solubility and precipitates. This is called the precipitin reaction.11 Figure 5.6 shows how the quantity of precipitin produced varies with the quantity of antigen added, for a fixed total antibody concentration. 

Hemagglutination refers to agglutination reactions in which the antigen is located on an eiythrocyte. Erythrocytes are not only good passive carriers of antigen, but are also easily coated with foreign proteins and can be easily obtained and stored. 

In general, the agglutination methods are quite sensitive but are not as quantitative as other immunochemical methods discussed thus far. Nonisotopic immunoassays, especially EIAs, are as convenient as agglutination reactions and are therefore replacing agglutination methods in many laboratories. 

A qualitative test for BTA analytes in urine, termed the BTA stat. test, has been developed. BTA analytes are high molecular weight polypeptides composed of complexes of basement membrane proteins. The presence of BTA analytes in urine is thought to involve either invasion of the basement membrane by tumor, production by the tumor itself, or a combination of these, which maybe linked with the bodjfs immune response. If BTA analytes are present in a significant level, they will combine with latex particles to produce an agglutination reaction, which produces a visible color change on the... 

Cross-agglutination reactions between T pes VII and XVIII Pneumococci were noted in 1932, prior to the isolation of the respective, specific, capsular polysaccharides. Chemical studies " showed that SXVIII (C ]d +96° nitrogen, 0.6% phosphorus, 3.1%) contains D-glucose, d-galactose, L-rhanmose, glycerol, phosphate, and 0-acetyl in the approximate ratios 3 1 1 1 1 1. 

In 1904, Dr. Karl Landsteiner performed a series of experiments on the blood of workers in his laboratory. His results explained the mysterious transfusion fatalities, and blood transfusions were reinstated as a lifesaving clinical tool. Landsteiner took blood samples from his coworkers. He separated the blood cells from the serum, the liquid component of the blood, and mixed these samples in test tubes. When he mixed serum from one individual with blood cells of another, Landsteiner observed that, in some instances, the serum samples caused clumping, or agglutination, of red blood cells (RBC). The agglutination reaction always indicated that the two bloods were incompatible and transfusion could lead to life-threatening reactions. As a result of many such experiments, Landsteiner showed that there are four human blood groups, designated A, B, AB, and O. 

Agglutination reaction A reaction of antibodies with antigens the results in agglutination, the clumping together of cells or... 

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