CA6 and infection: With a comparatively low level of samplereactivity against VP1 of EV71, CA16, CA5 and CA6 in EV-A (Fig. 2), the strong inhibition of the reactions by the VP1 ofEV-A viruses and of PV1 and CB3 (Fig.4a–d) and a highly significant correlation between theinhibition of the reactions by the VP1 of other EV-A viruses and of CB3 andPV1 (Table 1, Fig.S1) demonstrated that these antibody responses were mainly attributable tocross-reactive antibodies elicited by the infections of other EV-A virusesand of PV1 and CB3, with little contribution from specific antibodies.