Development of a novel Live Attenuated Influenza A Virus vaccine encoding the IgA-inducing protein

Authors: CACERES, JOAQUIN - University Of Georgia; CARDENAS-GARCIA, STIVALIS - University Of Georgia; JAIN, AARTI - University Of California Irvine; GAY, CLAIRE - University Of Georgia; CARNACCINI, SILVIA - University Of Georgia; SEIBERT, BRITTANY - University Of Georgia; FERRERI, LUCAS - University Of Georgia; GEIGER, GINDER - University Of Georgia; NAKAJIIMA, RIE - University Of California Irvine; PEREZ, DANIEL - University Of California Irvine; RAJAO, DANIELA - University Of Georgia; ISAKOVA-SIVAK, IRINA - Federal State Budgetary Scientific Institution "research Institute Of Experimental And Clinical Med; RUDENKO, LARISA - Federal State Budgetary Scientific Institution "research Institute Of Experimental And Clinical Med; Baker, Amy; DAVIES, HUW - University Of California Irvine

Submitted to: Vaccines
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/22/2021
Publication Date: 6/27/2021
Citation: Caceres, J.C., Cardenas-Garcia, S., Jain, A., Gay, C.J., Carnaccini, S., Seibert, B., Ferreri, L.M., Geiger, G., Nakajiima, R., Perez, D., Rajao, D.S., Isakova-Sivak, I., Rudenko, L., Vincent, A.L., Davies, H. 2021. Development of a novel Live Attenuated Influenza A Virus vaccine encoding the IgA-inducing protein. Vaccines. 9(7). Article 703. https://doi.org/10.3390/vaccines9070703.
DOI: https://doi.org/10.3390/vaccines9070703

Interpretive Summary: Seasonal influenza A virus (IAV) infections are among the most important respiratory diseases worldwide. Vaccination is considered the first line of defense against IAV, but virus evolution through genetic change makes vaccines less effective after a single season or against pandemic strains. Live attenuated influenza virus (LAIV) vaccines induce a combination of of immunity in the bloodstream and respiratory tract by mimicking a natural infection. To further enhance protective respiratory mucosal responses upon intranasal LAIV administration, we sought to incorporate a gene called IgA-inducing protein (IGIP), reported to enhance the production of IgA antibody found in the respiratory tract mucosa, into the LAIV. Mice were vaccinated with the modified IGIP-LAIV and antibodies from immunized mice were tested for binding to a panel of IAV. Serum and respiratory tract fluid from IGIP-LAIV vaccinated mice had a trend for higher antibody responses to IAV proteins. These results show that IAVs are amenable to the introduction of genes encoding immunomodulatory functions that can serve to improve LAIV. Such types of modifications could improve overall vaccine safety and efficacy and these studies are significant in the context of developing more efficacious vaccine approaches against influenza.

Technical Abstract: Seasonal influenza A virus (IAV) infections are among the most important respiratory diseases worldwide. Vaccination is considered the first line of defense against IAV, but antigenic drift makes vaccines less effective after a single season or against pandemic strains. Live attenuated influenza virus (LAIV) vaccines elicit a combination of systemic and mucosal immunity by mimicking a natural infection. To further enhance protective mucosal responses upon intranasal LAIV administration, we sought to incorporate into the LAIV genome the gene encoding the IgA-inducing protein (IGIP). IGIP was inserted in segment 4 at the N-terminus of the 2009 pandemic H1 HA ORF in the background of two LAIV backbones: the cold-adapted A/Leningrad/134/47/57 (H2N2) strain (caLen) and the experimental attenuated backbone A/turkey/Ohio/313053/04 (H3N2) (OH/04att). Incorporation of IGIP into the caLen background led to a virus (IGIP-H1caLen) that grew poorly in eggs and MDCK cells. In contrast, IGIP in the OH/04att background (IGIP-H1att) virus grew well to titers comparable to the isogenic backbone H1att (H1N1) without IGIP. The IGIP-H1att (H1N1) virus was substantially more attenuated than the isogenic H1att (H1N1) virus in DBA/2J mice. IGIP-H1att-vaccinated mice, like those vaccinated with the H1caLen vaccine but not the mock-vaccinated controls were protected against lethal challenge with a homologous virus. More importantly, the IGIP-H1att generated robust serum HAI responses in naïve mice against the homologous virus, equal or better than those obtained in mice that received the H1caLen (H1N1) vaccine. Analysis of IgG and IgA responses using a protein microarray containing a panel of group 1 and 2 HAs subtypes, N1, N2 and N9 NA subtypes, and M1, NP, NS1 and NS2 internal proteins, revealed qualitative differences in humoral responses between vaccine groups. Serum samples from IGIP-H1att-vaccinated mice showed clear trends towards increased stimulation of IgG responses compared to samples from H1caLen-vaccinated mice, not only against HA, but also against NA, NP, M1, and NS1. In agreement with this observation, bronchoalveolar lavage samples and to a lesser extent nasal wash samples, showed a trend towards increased IgG and IgA in the IGIP-H1att-vaccinated group compared to the H1caLen-vaccinated counterparts. These results show that IAVs are amenable to the introduction of genes encoding immunomodulatory functions that can serve as natural adjuvants within the context of a LAIV. Such types of modifications could improve overall vaccine safety and efficacy without sacrificing virus yield. Overall, these studies are significant in the context of developing more efficacious vaccine approaches against influenza.