摘要Background Previous serological studies of human bocavirus(HBoV)1 could not exclude cross-reactivity with the other three HBoVs,particularly HBoV2.Methods To search for genotype-specific antibodies against HBoV1 and HBoV2,the divergent regions(DRs)located on the major capsid protein VP3 were defined through viral amino acid alignment and structure prediction.DR-deduced peptides were used as antigens to harvest corresponding anti-DR rabbit sera.To determine their genotype specificities for HBoV 1 and HBoV2,these sera samples were used as antibodies against the antigens VP3 of HBoV1 and HBoV2(expressed in Escherichia coli)in western blotting(WB),enzyme-linked immunosorbent assay(ELISA),and bio-layer interferometry(BLI)assays.Subsequently,the antibodies were evaluated with clinical specimens from pediatric patients with acute respiratory tract infection by indirect immunofluorescence assay(IFA).Results There were four DRs(DR1-4)located on VP3 with different secondary and tertiary structures between HBoV1 and HBoV2.Regarding the reactivity with VP3 of HBoV1 or HBoV2 in WB and ELISA,high intra-genotype cross-reactivity of anti-HBoV1 or HBoV2 DR1,DR3,and DR4,but not anti-DR2,was observed.Genotype-specific binding capacity of anti-DR2 sera was confirmed by BLI and IFA,in which only anti-HBoV1 DR2 antibody reacted with HBoV1-positive respiratory specimens.Conclusion Antibodies against DR2,located on VP3 of HBoV1 or HBoV2,were genotype specific for HBoV1 and HBoV2,respectively.