New influenza vaccines that provide effective and broad protection are desperately needed. Live attenuated viruses are attractive vaccine candidates because they can elicit both humoral and cellular immune responses. However, recent formulations of live attenuated influenza vaccines (LAIVs) have not been protective. We combined high-coverage transposon mutagenesis of influenza virus with a rapid high-throughput screening for attenuation to generate W7-791, a live attenuated mutant virus strain. W7-791 produced only a transient asymptomatic infection in adult and neonatal mice even at doses 100-fold higher than the LD50 of the parent strain. A single administration of W7-791 conferred full protection to mice against lethal challenge with H1N1, H3N2, and H5N1 strains, and improved viral clearance in ferrets. Adoptive transfer of T cells from W7-791-immunized mice conferred heterologous protection, indicating a role for T cell-mediated immunity. These studies present an LAIV development strategy to rapidly generate and screen entire libraries of viral clones.
Bibliographical noteFunding Information:
We would like to thank Drs. Yuying Liang and David Sanchez for providing the influenza 8-plasmid reverse genetics system. We would like to thank Dr. Ren Sun for his help in the mutagenesis assay. This work was supported by grants from the Chinese Academy of Medical Sciences, including CAMS Initiative for?Innovative Medicine (2016-I2M-1-005), the institutional research fund for?Thousand Talents Program at the CAMS, the national special research fund for public welfare industry at the CAMS, and PUMC Youth Fund (3332015124); grants from the National Natural Science Foundation of China (91542201, 81590765, and 81501351); the Ministry of Health of China grant (201302018); Ministry of Science and Technology of China grant (2013CB911103); the national key scientific and technological special project of China for the development of major innovative drug (2015ZX09102023); the national special research fund for public welfare industry from the Ministry of Health and Family Planning of China (201302018); and NIH grants AI069120, AI056154, AI078389, and T32 AI089398.
© 2017 Elsevier Inc.
- flu vaccine
- genome-wide mutagenesis
- influenza vaccine
- matrix protein