IMMUNODOMINANT NEUTRALIZING ANTIGENS DEPEND ON THE VIRUS-STRAIN DURING A PRIMARY IMMUNE-RESPONSE IN CALVES TO BOVINE ROTAVIRUSES

Sera obtained from gnotobiotic calves (GC antisera) infected with bovi ne rotavirus strain NCDV or B223 from a previous study (Woode et al., 1987), which have different G (G6 and G10 respectively) and P serotype s, were compared for their neutralization (NT) properties to a number of human and animal rotaviruses (representing G serotype 1-6, 8-10). T wo distinct patterns of neutralization were identified from these GC a ntisera. Of all the serotypes tested, NCDV GC antisera neutralized onl y B641 to a relatively high titer compared with the homologous titer, implying a narrow pattern of NT response. Analysis with reassortants i ndicated that the response was primarily to VP4. In contrast, B223 GC antisera neutralized most of the G serotypes tested to titers within 3 -7 fold of the homologous titer, demonstrating a broad pattern of NT r esponse. In the earlier study B223 was shown to induce a heterotypic p rotection against bovine rotavirus B641 (G serotype 6), and the serolo gic data obtained from this study indicates that a B223 vaccine might provide broad protection against several different serotypes of human and animal rotaviruses.