Neutralizing monoclonal antibodies as effective therapeutics and prophylactics against lethal H10N7 avian influenza infection in a mouse model.

The H10 subtype of avian influenza virus (AIV) is widespread in poultry worldwide and poses a significant threat to animal health. With the emergence of sporadic and fatal cases in humans infected with H10 subtype AIVs in recent years, it is imperative to develop neutralizing monoclonal antibodies (mAbs) to treat influenza clinically. In this study, BALB/c mice were immunized with A/chicken/Zhejiang/2CP8/2014 (H10N7) haemagglutinin (HA) protein, and eight HA-specific mAbs were subsequently screened. The characteristics of the mAbs were tested and evaluated using haemagglutination inhibition and microneutralization assays in vitro. We selected two mAbs (1E10 and 2A9) to further study their characteristics and functions, including their affinity and specificity of binding to antigens via enzyme-linked immunosorbent assays and immunofluorescence assays. We identified the mutant epitopes (K165E and N170D) of the H10N7 strain produced under the immune pressure of the two mAbs. Furthermore, we infected mice with the H10N7 virus and conducted prophylactic and therapeutic trials using the two mAbs. The results indicated that both mAbs have obvious neutralization ability in vivo. Compared with those in the isotype IgG control group, the weights of the mice in the experimental groups were greater in the prophylactic and therapeutic experiments. In conclusion, the mAbs produced in this study are expected to be effective drugs for clinical antiviral therapy against lethal infection by H10 AIVs.