Agglutination of Legionella pneumophila by antiserum is accelerated in an ultrasonic standing wave.
The agglutination of Legionella pneumophila (LP) by diluted anti-LP whole rabbit serum has been compared in conventional microwell plates and in capillary containers where the suspension was exposed to a 1 MHz ultrasonic standing wave field. A positive reaction in the standing wave field was detected as a series of cell agglutinates, separated by half an acoustic wavelength (0.75 mm), distributed along the length of the capillary. Agglutination occurred in 60 s or less with ultrasound, while the incubation period for a positive microwell test was often of the order of hours. At a given antiserum concentration, ultrasound-induced agglutination occurred at LP concentrations two-fold lower than those giving a positive result in the microwell plate assays. At cell concentrations near the lower limit for detection of a positive result in the microwell plates a positive reaction was detected in the standing wave field at antiserum concentrations up to 500-fold lower than those forming visible precipitates in the conventional assay.
Jepras
R I
RI
Division of Biotechnology, PHLS Centre for Applied Microbiology and Research, Porton Down, Salisbury, U.K.
Clarke
D J
DJ
Coakley
W T
WT
D000371:Agglutination; D000907:Antibodies, Bacterial / Q000276:immunology; D000937:Antigen-Antibody Reactions; D066298:In Vitro Techniques; D007875:Legionella / Q000276:immunology*; D013997:Time Factors; D014465:Ultrasonics
D000907:Antibodies, Bacterial