Effective intranasal therapeutics and prophylactics with monoclonal antibody against lethal infection of H7N7 influenza virus.

Recurrence of highly pathogenic avian influenza (HPAI) virus subtype H7 in humans and poultry continues to be a serious concern to public health. No effective prevention and treatment are currently available against H7 infection. One H7 monoclonal antibody, Mab 62 was selected and characterized. Mab 62 presented efficient neutralization activity against all six representative H7 strains tested, including the H7N9 strain from the recent outbreak in China. The epitope of 62 identified on H7 HA1 exists in all the human H7 strains, including the recent H7N9 strains from China. Mab 62 when administered passively, pre or post challenge with 5 MLD50 (50% mouse lethal dose) HPAI H7N7 influenza viruses could protect 100% of the mice from death. The efficacy of intranasal administration of the Mab was evaluated versus the intraperitoneal route. In the therapeutic study, body weight loss and virus load were reduced in intranasally inoculated mice, as compared to the intraperitoneal group. Intranasal administration results in early clearance of the virus from the lungs and completely prevents lung pathology of H7N7. The study confirmed that intranasal administration of Mab 62 is either an effective prophylactic or therapeutic means against H7 lethal infection. The results of epitope analysis suggest the potential of Mab 62 to be used for the efficacious prevention and treatment against the recent human H7N9 strains.