Immunization with Live Attenuated Influenza Viruses That Express Altered NS1 Proteins Results in Potent and Protective Memory CD8+ T-Cell Responses▿

• Type of Material: Article
• Authors: Scott N. Mueller, Emory University; William A. Langley, Emory University; Elena Carnero, Emory University; Adolfo Garcia-Sastre, Mount Sinai Hospital; Rafi Ahmed, Emory University
• Language: English
• Date: 2010-02
• Publisher: American Society for Microbiology
• Publication Version: Final Published Version
• Copyright Statement: © 2010, American Society for Microbiology
• Final Published Version (URL): http://jvi.asm.org/content/84/4/1847.full
• Title of Journal or Parent Work: Journal of Virology
• ISSN: 0022-538X
• Volume: 84
• Issue: 4
• Start Page: 1847
• End Page: 1855
• Grant/Funding Information: This study was supported by grant U01 AI70469 from NIAID (to A.G.-S. and R.A.) and by CRIP (Center for Research on Influenza Pathogenesis; NIAID contract HHSN266200700010C to A.G.-S.).; E.C. was the recipient of a postdoctoral fellowship from the Fundacion Ramon Areces.
• Research Categories: Health Sciences, Immunology; Biology, Microbiology

Abstract

The generation of vaccines that induce long-lived protective immunity against influenza virus infections remains a challenging goal. Ideally, vaccines should elicit effective humoral and cellular immunity to protect an individual from infection or disease. Cross-reactive T- and B-cell responses that are elicited by live virus infections may provide such broad protection. Optimal induction of T-cell responses involves the action of type I interferons (IFN-I). Influenza virus expressed nonstructural protein 1 (NS1) functions as an inhibitor of IFN-I and promotes viral growth. We wanted to examine the priming of CD8+ T-cell responses to influenza virus in the absence of this inhibition of IFN-I production. We generated recombinant mouse-adapted influenza A/PR/8/34 viruses with NS1 truncations and/or deletions that also express the gp33-41 epitope from lymphocytic choriomeningitis virus. Intranasal infection of mice with the attenuated viruses primed long-lived T- and B-cell responses despite significantly reduced viral replication in the lungs compared to wild-type virus. Antigen-specific CD8+ T cells expanded upon rechallenge and generated increased protective memory T-cell populations after boosting. These results show that live attenuated influenza viruses expressing truncated NS1 proteins can prime protective immunity and may have implications for the design of novel modified live influenza virus vaccines.