Introduction
The rapid spread of infectious diseases poses a significant global threat, with seasonal influenza viruses alone causing 290,000 to 650,000 deaths annually. The emergence of highly pathogenic strains such as H5N1 and H7N9 from animal reservoirs further increases pandemic risks. Developing effective vaccines and therapeutics is crucial, yet the evaluation of these interventions is often limited by the need for high biosafety containment facilities. To address these challenges, researchers have developed S-Lux, a replication-deficient, single-cycle recombinant influenza virus that expresses firefly luciferase (Flux) as a reporter protein. This innovation allows for real-time monitoring of viral infection in vivo and facilitates therapeutic antibody evaluation in lower-containment facilities.
Development of S-Lux and ES-Lux Systems
The S-Lux system is based on the single-cycle influenza vaccine S-FLU, where the hemagglutinin coding sequence is replaced with the Flux reporter protein. This system can be pseudotyped with haemagglutinin from avian influenza strains such as H5 and H7, enabling its use in standard BSL-2 facilities. In addition, the ES-Lux system was developed by pseudotyping with the Ebola Glycoprotein (GP), allowing for the evaluation of Ebola GP-targeting antibodies in vivo.
Methodology
The study utilized a replication-deficient, single-infectious cycle recombinant influenza virus expressing the firefly luciferase reporter protein in the H1N1 PR8 influenza strain background. Specific modifications were made to the S-HA Flu genome to achieve this. The resulting S-Lux strain retains all PR8 elements except for the hemagglutinin coding sequence, which is replaced with the flux coding sequence. Viable PR8 S-Lux virus particles were rescued by supplying the A/PR/8/1934 HA gene in trans by transient transfection.
In Vivo Evaluation
In vivo experiments demonstrated that S-Lux infection in mice resulted in dose-dependent bioluminescent expression in the airways. This allowed for the evaluation of neutralizing monoclonal antibodies and the clearance of infected cells. The S-Lux system proved to be a valuable tool for studying influenza virus tropism in the airways, particularly in newly isolated strains or those with pandemic potential.
Applications and Implications
The S-Lux and ES-Lux systems enable robust, simple, and time-efficient assessment of antiviral therapies targeting influenza and Ebola viruses in vivo. This approach overcomes the biosafety constraints that limit traditional efficacy studies. The ability to conduct these studies in lower-containment facilities significantly reduces experimental costs and increases accessibility for researchers.
Conclusion
The development of the S-Lux and ES-Lux systems represents a significant advancement in the evaluation of treatment strategies for highly infectious diseases. By facilitating real-time monitoring of viral infections and enabling the assessment of therapeutic antibodies in lower-containment facilities, these systems offer a promising tool for advancing global health efforts against pandemic threats.
🔗 **Fuente:** https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2025.1608074/full