PROTECTION AGAINST THE MOUSE-ADAPTED A FM/1/47 STRAIN OF INFLUENZA A VIRUS IN MICE BY A MONOCLONAL-ANTIBODY WITH CROSS-NEUTRALIZING ACTIVITY AMONG H1 AND H2 STRAINS/

The monoclonal antibody designated C179 was found to neutralize all of the H1 and H2 strains of influenza A virus studied (Y. Okuno, Y. Iseg awa, F. Sasao, and S. Ueda, J. Virol. 67:2552-2558, 1993). In the pres ent study, the ability of C179 to protect mice from the lethal effect of the A/FM/1/47 (H1N1) strain was examined. When the mice were inject ed intraperitoneally with 100 mu g of C179 per mouse a day before the virus challenge (2.0 x 10(3) focus-forming units per mouse), all of th e mice survived. Moreover, significantly higher survival rates were ob served in mice receiving 1,000 mu g of C179 per mouse 2 days after the virus challenge than in those receiving phosphate-buffered saline alo ne. These results indicate that C179 is effective not only for prevent ion but also for treatment of mice infected with H1 and H2 strains. Th e possibility that C179 can be used for passive immunization in humans is discussed.