AWWA QTC98237

AWWA QTC98237 High Affinity IgG1 Antibodies to Cryptosporidium and Giardia Give Improved Recoveries from Water Samples Using Immunomagnetic Separation (IMS)
Conference Proceeding by American Water Works Association, 01/01/1998

Scandizzo, P.; Vesey, G.; Gauci, M.; Baer, D.; Veal, D.A.

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The development of a highly efficient immunomagnetic separation (IMS) procedure for the selective isolation of Cryptosporidium oocysts and Giardia cysts from a range of water samples is described. The efficiency of the IMS procedure was evaluated on a range of water types. The optimised system developed used highly specific IgG1 antibodies to Cryptosporidium oocysts and Giardia cysts conjugated to paramagnetic beads. Using the optimized procedure, recoveries for Cryptosporidium oocysts from concentrated water samples averaged 87% with a standard deviation of 6% and recovery of Giardia cysts averaged 84% with a standard deviation of 12%. Evaluation of commercially available IMS kits which use IgM and IgG3 antibodies have resulted in recoveries of oocysts of less than 50% from the various water types tested. Selective enrichment of concentrated water samples with the IMS procedure reduced the time required to analyse the samples by fluorescence activated cell sorting (FACS) to between 5 and 7 min and subsequent visualization and enumeration by microscopy was reduced to between 5 and 16 min when IMS was used to isolate oocysts and cysts from environmental water samples prior to FACS analysis. The system allows for the simultaneous treatment of up to 24 samples and subsequent analysis by FACS and enumeration using microscopy. The system provides consistent and rapid recovery from a wide range of water samples and compliments the use of flow cytometry.