Friday, November 21, 2003

Description
Agglutination Assay


Procedure
Bacterial agglutination is performed using either P.
aeruginosa cells autoclaved at 120oC for 1 hour, then centrifuged and resuspended in saline or live P. aeruginosa cells grown to mid log phase, then centrifuged and resuspended in saline. (For either method
resuspend the bacteria so the concentration is 5 X 108 bacteria/ml.)

In both methods the cell preparations are incubated with serial dilutions of antiserum for 1 hour at 37oC. The agglutination of live cells is characterized by a coarse granular bacterial clumping, as opposed to the finer granular clumping of heat-killed P. aeruginosa with homologous LPS O-antigen-specific serum. Bacterial agglutination is scored on a scale of +1 (weak agglutination) to +4 (strong reaction). The agglutination can also be performed on glass slides using a drop each of antiserum and bacterial preparation, and the results observed after 3 to 5 minutes.


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