Sequence alignment showed a high amino acid identity of VP2 between HBoV species, with 77.5% identity between HBoV1 and HBoV2, 77.7% identity between HBoV1 and HBoV3, 77.5% identity between HBoV1 and HBoV4, 89.4% identity between HBoV2 and HBoV3, 88.5% identity between HBoV2 and HBoV4, and 90.9% identity between HBoV3 and HBoV4 (data not shown), indicating possible cross-reactivity between HBoV species. To evaluate the potential cross-reactivities, we examined the reactivity between the HBoV1-4 VLPs and purified mouse antisera against HBoV1, 2, 3, and 4 VP2 using Western blot and ELISA assays.