Monoclonal antibodies against the K99 antigen of Escherichia coli for diagnostic purposes.

Hybridomas secreting monoclonal antibodies against the K99 antigen of Escherichia coli were produced by the fusion of spleen cells from immunized BALB/c mice with P3/X63-Ag8.653 myeloma cells. The seven hybridomas which produced the highest antibody titers in vitro, as detected by enzyme-linked immunosorbent assay (ELISA) and Perma slide agglutination test (PSAT), were chosen for antibody production in vivo. No cross reaction was observed with K88ab, F41 and P987 antigens in the ELISA. The titer of each ascitic fluid was established by the ELISA and the slide agglutination (SAT) tests. The two ascitic fluids with the highest titer in the SAT were incorporated into the set of antisera used for serotyping at our laboratory. The results were satisfactory both in terms of stability and specificity.