Adjuvants are substances added to vaccines to enhance antigen-
specific immune responses or to protect antigens from
rapid elimination. As pattern recognition receptors, Toll-like
receptors 7 (TLR7) and 8 (TLR8) activate the innate immune
system by sensing endosomal single-stranded RNA of RNA
viruses. Here, we investigated if a 2,4-diaminoquinazolinebased
TLR7/8 agonist, (S)-3-((2-amino-8-fluoroquinazolin-
4-yl)amino)hexan-1-ol (named compound 31), could be used
as an adjuvant to enhance the serological and mucosal immunity
of an inactivated influenza A virus vaccine. The compound induced
the production of proinflammatory cytokines in macrophages.
In a dose-response analysis, intranasal administration
of 1 μg compound 31 together with an inactivated vaccine
(0.5 μg) to mice not only enhanced virus-specific IgG and
IgA production but also neutralized influenza A virus with
statistical significance. Notably, in a virus-challenge model,
the combination of the vaccine and compound 31 alleviated
viral infection-mediated loss of body weight and increased
survival rates by 40% compared with vaccine only-treated mice.
We suggest that compound 31 is a promising lead compound
for developing mucosal vaccine adjuvants to protect against
respiratory RNA viruses such as influenza viruses and potentially
coronaviruses.
Citations
Citations to this article as recorded by
Efflux-Enhanced Imidazoquinolines To Exploit Chemoresistance Muhammad Haroon, Sharmin Sultana, Seyedeh A. Najibi, Emily T. Wang, Abbey Michaelson, Pranto S. M. Al Muied, Amy E. Nielsen, Rock J. Mancini ACS Omega.2025;[Epub] CrossRef
Design, Synthesis, and Biological Evaluation of New 2,6,7-Substituted Purine Derivatives as Toll-like Receptor 7 Agonists for Intranasal Vaccine Adjuvants Morgan Kim, Kyungseob Noh, Pyeongkeun Kim, Jae Ho Kim, Byeong Wook Choi, Ravi Singh, Jun-Ho Choi, Soo Bong Han, Seong Soon Kim, Eun-Young Lee, Myung Ae Bae, Daeho Shin, Meehyein Kim, Jin Hee Ahn Journal of Medicinal Chemistry.2024; 67(11): 9389. CrossRef
Evaluation of Antiviral Activity of Gemcitabine Derivatives against Influenza Virus and Severe Acute Respiratory Syndrome Coronavirus 2 Hyeon-Min Cha, Uk-Il Kim, Soo Bin Ahn, Myoung Kyu Lee, Haemi Lee, Hyungtae Bang, Yejin Jang, Seong Soon Kim, Myung Ae Bae, Kyungjin Kim, Meehyein Kim ACS Infectious Diseases.2023; 9(4): 1033. CrossRef
Identification of broad-spectrum neutralizing antibodies against influenza A virus and evaluation of their prophylactic efficacy in mice Sumin Son, Soo Bin Ahn, Geonyeong Kim, Yejin Jang, Chunkyu Ko, Meehyein Kim, Sang Jick Kim Antiviral Research.2023; 213: 105591. CrossRef
Inhibition of KIF20A suppresses the replication of influenza A virus by inhibiting viral entry Hoyeon Jeon, Younghyun Lim, In-Gu Lee, Dong-In Kim, Keun Pil Kim, So-Hee Hong, Jeongkyu Kim, Youn-Sang Jung, Young-Jin Seo Journal of Microbiology.2022; 60(11): 1113. CrossRef