Intranasal Administration of Integrase Defective Lentiviral Vectors Expressing mAbs Protects from H5 Influenza Virus Challenge In Vivo

Abstract

BackgroundDespite medical advances, we are often unable to rapidly protect non-immune populations from infectious agents. Passive immunotherapy is a fast method of protection, but large-scale administration of monoclonal antibodies (mAbs) in unpractical. The delivery of mAbs using a viral vector can be an attractive alternative to direct mAbs injection. Integrase-defective lentiviral vectors (IDLV) have several advantages including the absence of pre-existing anti-vector immunity and the safety features of non-integration and non-replication. IDLV are maintained in non-dividing cells, and can express steady levels of functional proteins in vivo. We engineered IDLV to express mAbs against the influenza A virus (IAV) hemagglutinin, and tested their ability to protect from IAV in vivo.MethodsIDLV were produced by co-transfection of transfer, packaging, and envelope plasmids in 293T cells and purification on sucrose gradients. IDLV were normalized using a colorimetric reverse transcriptase assay. Plasmid expressing mAb VN04-2 was provided by B. Hanson. mAb in the supernatant of transduced cells were detected by western blot and quantified by the Easy-Titer Human IgG Assay Kit. For in vivo studies, groups of 6–8 weeks old mice received IDLV either by intranasal (in) or intramuscular (im) route. mAb production was detected by western blot and ELISA. Mice were challenged using the recombinant IAV VNH5N1-PR8/CDC-RG derived from IAV A/Vietnam/1203/2004.ResultsWe engineered IDLV producing the humanized mAb VN04-2 (IDLV-VN4-2), which is broadly neutralizing against H5 IAV. We found that after transduction of 293T cell with different dosages IDLV-VN4-2, the production of mAb was time and dose dependent. mAb were also functional, and bind specifically H5 HA but not other IAV proteins. We also measured VN04-2 production in the serum of mice 3, 6, 9, 14, 21 and 30 days after in or im administration of IDLV-VN4-2. We found that levels of mAb were sustained. In separate experiments 5/5 mice receiving IDLV-VN4-2 by the in route and 2/5 mice receiving it by the im route were protected from lethal IAV challenge.ConclusionOur data suggest that IDLV may represent an attractive candidate for vector-mediated immunization against infectious disease.Disclosures All authors: No reported disclosures.