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- The efficacy of a 2,4-diaminoquinazoline compound as an intranasal vaccine adjuvant to protect against influenza A virus infection in vivo
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Kyungseob Noh , Eun Ju Jeong , Timothy An , Jin Soo Shin , Hyejin Kim , Soo Bong Han , Meehyein Kim
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J. Microbiol. 2022;60(5):550-559. Published online April 18, 2022
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DOI: https://doi.org/10.1007/s12275-022-1661-7
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Abstract
- 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.
- Antiviral effects of human placenta hydrolysate (Laennec) against SARS-CoV-2 in vitro and in the ferret model
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Eun-Ha Kim , Young-il Kim , Seung-Gyu Jang , Minju Im , Kyeongsoo Jeong , Young Ki Choi , Hae-Jung Han
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J. Microbiol. 2021;59(11):1056-1062. Published online October 6, 2021
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DOI: https://doi.org/10.1007/s12275-021-1367-2
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Abstract
- The COVID-19 pandemic has caused unprecedented health,
social, and economic crises worldwide. However, to date, there
is an only a limited effective treatment for this disease. Human
placenta hydrolysate (hPH) has previously been shown to be
safe and to improve the health condition in patients with hyperferritinemia
and COVID-19. In this study, we aimed to
determine the antiviral effects of hPH against SARS-CoV-2
in vitro and in vivo models and compared with Remdesivir,
an FDA-approved drug for COVID-19 treatment. To assess
whether hPH inhibited SARS-CoV-2 replication, we determined
the CC50, EC50, and selective index (SI) in Vero cells
by infection with a SARS-CoV-2 at an MOI of 0.01. Further,
groups of ferrets infected with 105.8 TCID50/ml of SARS-CoV-2
and treated with hPH at 2, 4, 6 dpi, and compared their clinical
manifestation and virus titers in respiratory tracts with
PBS control-treated group. The mRNA expression of immunerelated
cytokines was determined by qRT-PCR. hPH treatment
attenuated virus replication in a dose-dependent manner in
vitro. In a ferret infection study, treatment with hPH resulted
in minimal bodyweight loss and attenuated virus replication
in the nasal wash, turbinates, and lungs of infected ferrets.
In addition, qRT-PCR results revealed that the hPH treatment
remarkably upregulated the gene expression of type I
(IFN-α and IFN-β) and II (IFN-γ) IFNs in SARS-CoV-2 infected
ferrets. Our data collectively suggest that hPH has antiviral
efficacy against SARS-CoV-2 and might be a promising
therapeutic agent for the treatment of SARS-CoV-2 infection.
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