RESPONSE TO WC3 ROTAVIRUS VACCINE IN COLOSTRUM-DEPRIVED CALF MEASURED BY ELISA AND VIRUS NEUTRALIZATION BY PLAQUE REDUCTION

A rotavirus of bovine origin (WC3 strain) isolated from a calf in Pennsylvania was adapted to tissue culture for the evaluation of a candidate vaccine for children. A two-day-old calf was orally administered 15 ml (1 × 107pfu/ml) of WC3 rotavirus vaccine. No clinical sequelae were detected and shedding of virus in faeces was detected in a limited time only. ELISA, plaque assay and RNA electrophoresis were employed to detect shed virus in faecal samples. Analysis of post-vaccinal faecal samples by PAGE-ss and ELISA did not reveal the presence of virus. Faecal samples analysed by plaque assay at day 5 and day 7 post-vaccination revealed plaque-forming virus. The antibody response was measured by virus neutralization in a plaque reduction test. The PRN antibody titre in day zero serum (pre-immunization) was insignificant against WC3 and also against the human serotype SA11, but significant against the human serotypes WA and WI061. After administration of WC3, antibody titres against WC3 and SA11 increased while the titre against WA decreased.