Agglutination Reaction

Antibodies can agglutinate antigen-loaded particles (Fig. 2.25), whilst antigens can agglutinate antibody-loaded particles. Application: agglutination of bacteria or erythrocytes (e.g., blood group tests).

Kayser, Medical Microbiology © 2005 Thieme

All rights reserved. Usage subject to terms and conditions of license.

— Immunoelectrophoresis According to Grabar and Williams

Undiluted serum

Antihuman serum

Albumin

Undiluted

Anti-IgG, anti-IgA, anti-IgM

Fig. 2.23 Serum is separated within agarose by an electric field, and rendered visible with anti-serum directed against human serum (above), or with selected specific antibodies (below).

■ Indirect hemagglutination. An antigen is fixed on the surface of erythrocytes and the antigen-loaded erythrocytes are then agglutinated using specific antibodies.

■ Hemagglutination inhibition test. The ability of a sample containing antigen to inhibit hemagglutination between antigen-loaded erythrocytes and antiserum is measured. This test is frequently used to quantify antibodies against hemagglutinating viruses (mainly influenza and parainfluenza viruses).

■ Antiglobulin tests according to Coombs. The direct Coombs test determines antibody binding directly to erythrocytes (e.g., anti-Rh antibodies agglutinate Rh+ erythrocytes of neonates). The indirect Coombs test is suitable for detection of antibodies that have already bound to the Rh+ erythrocytes of newborns (second pregnancy or sensitized mother), or which have been in-

Kayser, Medical Microbiology © 2005 Thieme

All rights reserved. Usage subject to terms and conditions of license.

Western Blotting

Antigen samples e

Nitrocellulose filter

Western Blotting

Antigen samples

Nitrocellulose filter

Transfer

III -

Separated proteins

Incubation with specific Ab, washing, addition of labeled anti-lg

Autoradioqram

Incubation with specific Ab, washing, addition of labeled anti-lg

Autoradiog- ^ ^raphy Filter rewash or enzyme reaction

Fig. 2.24 Antigen samples separated in a gel are transferred to nitrocellulose. Non-specific binding of the antibodies to the filter is then prevented with serum albumin or irrelevant proteins that do not cross-react with any of the antibodies used. Antibodies specific for the antigens being sought are then added. Once immune complexes have formed, the unbound antibodies are thoroughly washed away and the remaining bound antibodies are labeled using anti-immunoglobulin antibodies. These are in turn rendered visible by the autoradiographic procedure.

Autoradioqram

cubated in vitro with erythrocytes or antigenic particles. In all cases agglutination is detected using anti-Ig antibodies. Antigens can also be adsorbed to latex.

Essentials of Human Physiology

Essentials of Human Physiology

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  • Rina Mazzi
    Can algal cells agglutinate?
    6 years ago

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