PT - JOURNAL ARTICLE AU - Adrian Rice AU - Mohit Verma AU - Annie Shin AU - Lise Zakin AU - Peter Sieling AU - Shiho Tanaka AU - Joseph Balint AU - Kyle Dinkins AU - Helty Adisetiyo AU - Brett Morimoto AU - Justin Taft AU - Roosheel Patel AU - Sofija Buta AU - Marta Martin-Fernandez AU - Dusan Bogunovic AU - Patricia Spilman AU - Elizabeth Gabitzsch AU - Jeffrey T. Safrit AU - Shahrooz Rabizadeh AU - Kayvan Niazi AU - Patrick Soon-Shiong TI - The Dual-Antigen Ad5 COVID-19 Vaccine Delivered as an Intranasal Plus Subcutaneous Prime Elicits Th1 Dominant T-Cell and Humoral Responses in CD-1 Mice AID - 10.1101/2021.03.22.436476 DP - 2021 Jan 01 TA - bioRxiv PG - 2021.03.22.436476 4099 - http://biorxiv.org/content/early/2021/03/23/2021.03.22.436476.short 4100 - http://biorxiv.org/content/early/2021/03/23/2021.03.22.436476.full AB - In response to the need for an efficacious, thermally-stable COVID-19 vaccine that can elicit both humoral and cell-mediated T-cell responses, we have developed a dual-antigen human adenovirus serotype 5 (hAd5) COVID-19 vaccine in formulations suitable for subcutaneous (SC), intranasal (IN), or oral delivery. The vaccine expresses both the SARS-CoV-2 spike (S) and nucleocapsid (N) proteins using an hAd5 platform with E1, E2b, and E3 sequences deleted (hAd5[E1-, E2b-, E3-]) that is effective even in the presence of hAd5 immunity. In the vaccine, S is modified (S-Fusion) for enhanced cell-surface display to elicit humoral responses and N is modified with an Enhanced T-cell Stimulation Domain (N-ETSD) to direct N to the endosomal/lysosomal pathway to increase MHC I and II presentation. Initial studies using subcutaneous (SC) prime and SC boost vaccination of CD-1 mice demonstrated that the hAd5 S-Fusion + N-ETSD vaccine elicits T-helper cell 1 (Th1) dominant T-cell and humoral responses to both S and N. We then compared SC to IN prime vaccination with either an SC or IN boost post-SC prime and an IN boost after IN prime. These studies reveal that IN prime/IN boost is as effective at generating Th1 dominant humoral responses to both S and N as the other combinations, but that the SC prime with either an IN or SC boost elicits greater T cell responses. In a third study to assess the power of the two routes of delivery when used together, we used a combined SC plus IN prime with or without a boost and found the combined prime alone to be as effective as the combined prime with either an SC or IN boost in generating both humoral and T-cell responses. The findings here in CD-1 mice demonstrate that combined SC and IN prime-only delivery has the potential to provide broad immunity – including mucosal immunity – against SARS-CoV-2 and supports further testing of this delivery approach in additional animal models and clinical trials.Competing Interest StatementAll authors with an ImmunityBio affiliation have a role in the development of the vaccine described.