Cross reactivity among human enterovirus serotypes as revealed by microneutralization assay technique

Paired or tripled serum specimens examined for cross reactions between poliomyelitis viruses and other non-polio enteroviruses were obtained from 356 patients (217 males and 139 females) with various clinical diagnoses (aseptic meningitis, meningoencephalitis, paretic neuro-infections, upper respiratory tract infections, bronchopneumonia) who were sampled in 1984 and 1985. The sera were examined by the microneutralization assay technique in flat-bottomed 96-well polyvinyl chloride plates against 100-300 TCD50 of these enterovirus serotypes: CA9, CB1-CB5, E1, E2, E4-E9, E17, E20, E24, E30, EV71 and polioviruses P1-P3. The tests were carried out on BGM or RD cells. Confirmed significant seroconversions to at least one enterovirus serotype were observed in 87 (24.2%) patients. Of these, 27 (31%) reacted by parallel significant or insignificant increases in the heterotypic antibody titre to poliovirus, which accounted for 7.6% of all patients examined. Heterotypic antibody responses may become source of errors in individuals examined for poliovaccine efficacy or the state of specific immunity response to polio, but are unlikely to discredit the overall outcomes of the seroepidemiological surveys conducted in the general population.