Structure and Function Analysis of an Antibody Recognizing All Influenza A Subtypes

Kallewaard, Nicole L.; Corti, Davide; Collins, Patrick J.; Neu, Ursula; McAuliffe, Josephine M.; Benjamin, Ebony; Wachter-Rosati, Leslie; Palmer-Hill, Frances J.; Yuan, Andy Q.; Walker, Philip A.; Vorlaender, Matthias K.; Bianchi, Siro; Guarino, Barbara; De Marco, Anna; Vanzetta, Fabrizia; Agatic, Gloria; Foglierini, Mathilde; Pinna, Debora; Fernandez-Rodriguez, Blanca; Fruehwirth, Alexander; Silacci, Chiara; Ogrodowicz, Roksana W.; Martin, Stephen R.; Sallusto, Federica; Suzich, JoAnn A.; Lanzavecchia, Antonio; Zhu, Qing; Gamblin, Steven J.; Skehel, John J.

All murine study protocols were approved and conducted in accordance with MedImmune's Institutional Animal Care and Use Committee and subsequently performed in an Association for the Assessment and Accreditation of Laboratory Animal Care (AAALAC)-certified facility. Six-to eight-week-old BALB/c mice (Harlan Laboratories) were used in these studies. Mice were weighed on the day of or 1 day before virus challenge and monitored daily for 14 days for weight loss and survival (mice with body weight loss of ≥25% were euthanized). For the study of prophylactic and therapeutic efficacy, mice were infected intranasal with 3 x MLD50 of CA/2009 (9.5 x 10 4 TCID50/mouse); 5x MLD50 of WSN/33 (6 x 10 2 TCID50/mouse); 7 x MLD50 of rHK/68 (3.6 x 10 4 TCID50/mouse) on Day 0. Animals administered a single IP dose of 10 mg/kg, 3 mg/kg, or 1 mg/kg of MEDI8852 on Day 0, Day 1, Day 2, Day 3, or Day 4 post-infection, depending on the virus strain. For oseltamivir comparison studies, mice were administered 25 mg/kg oseltamivir PO BID for 5 days, or a single dose of MEDI8852 10mg/kg IV with equivalent volume of vehicle given PO BID for 5 days to mimic the hydration of oseltamivir treated animals. To assess virus load in the lungs, four mice from each group were euthanized on Day 5 post-infection. Whole lungs were homogenized in 10% (wt/vol) sterile L15 medium (Invitrogen) and titrated on MDCK cells to determine the TCID 50 /gram of tissue. Lung function was measured using the MouseOx™ Pulse-oximeter infrared sensor collar clip (Starr Life Sciences, Oakmont PA) to determine the percent blood SpO2 of mice on day 6 post infection. The ferret H5N1 study was completed under contract at Southern Research Institute (Birmingham, Alabama). Five-to-six months' old influenza sero-negative ferrets (Triple F Farms) were challenged intranasally with 1 LD90 of A/Vietnam/1203/04 (H5N1) highly pathogenic avian influenza virus in 1.0 ml (approximately 0.5 ml/nare). Infected animals were treated with either a single IV dose of MEDI8852 at 25 mg/kg, oseltamivir at 25 mg/kg BID for 5 days initiated at 1, 2, or 3 days post infection. Control-treated animals received a 25 mg/kg IV dose of isotype control monoclonal antibody on Day 1 post-infection. Bio-metric data systems chip was implanted between the shoulder blade for identification and temperature monitoring. Animals were monitored for weight loss, fever, clinical signs, and survival.