ABILITY OF HUMAN SERA TO NEUTRALIZE THE ACTIVITY OF VERO CYTOTOXINS VT1, VT2 AND VARIANT FORMS OF VT2

Sera, from 17 patients with diarrhoea or haemolytic uraemic syndrome, and six healthy adults, were tested for neutralisation of Vero cytotox ins (VT). For all 17 patients there was evidence of infection with Esc herichia coli 0157. Sera from two controls but from none of the patien ts neutralised VT1, although two patients were infected by strains pro ducing VT1 and vn. sera from all six controls and 14 patients neutrali sed VT2 derived from strains 933 and E32511, but not variant forms of VT2 derived from strains E32511, E57, B2F1 and H.1.8. This neutralisin g activity warrants further investigation, especially as many 0157 VTE C carry both VT2 and VT2 variant genes.