Protection and antibody responses to oral priming by attenuated human rotavirus followed by oral boosting with 2/6-rotavirus-like particles with immunostimulating complexes in gnotobiotic pigs

Abstract We evaluated antibody responses and protection induced by attenuated Wa human rotavirus (AttHRV) and VP2/6-rotavirus-like particles (VLP), 100 or 250 μg/dose, with immunostimulating complexes (ISCOM) (VLP/ISCOM) each given orally, alone or sequentially to gnotobiotic pigs. The AttHRV-VLP 250 μg/ISCOM and three-dose-AttHRV (AttHRV3×) groups had significantly higher serum IgA, IgG and intestinal IgA antibody titers to HRV pre-challenge than the three-dose-VLP 100 μg/ISCOM group (VLP/ISCOM3×) and controls (diluent/ISCOMmatrix). Protection rates against viral shedding and diarrhea were highest in the AttHRV-VLP250 μg/ISCOM and AttHRV3× groups, lower in the AttHRV-VLP 100 μg/ISCOM group, with no protection in the VLP/ISCOM3× group and controls. Thus, VLP/ISCOM boosted antibody titers and protection after priming with AttHRV.