New Emerging Infectious Diseases

Immunopathology, Protective Immunity & Vaccines

  • New Emerging Infectious Diseases

In the field of new emerging viral infectious diseases, our lab. has focused on immunopathological mechanisms of immune cells that contribute to pathogenesis and severity of the disease in new emerging infectios diseases.

During the COVID-19 pandemic, we have participated in immunological research on SARS-CoV-2 infection and COVID-19. In this study, we performed scRNA-seq using sequential BAL fluid samples obtained from SARS-CoV-2-infected ferrets, and found that specific subclusters of NK cells and CD8 T cells exhibited increased responses to IFN during the early phase of SARS-CoV-2 infection.

Moreover, we identified 10 different subpopulations that exhibited relative proportional changes during the natural course of infection, and revealed distinctive and stepwise differentiation from monocyte-derived infiltrating macrophages towards M1 or M2 macrophages (Nature Communications 2021)

Currently, we are studying immunological changes in SARS-CoV-2-specific B cells during natural course of SARS-CoV-2 infections in COVID-19 patients. Moreover, we are investigating distinct characteristics of COVID-19 vaccine-induced B cells, compared to infection-induced B cells.

We are studying detailed characteristics of SARS-CoV-2-specific immune cells using human clinical samples from COVID-19 patients and vaccinated individuals, which would help to provide insights into the development of novel preventive vaccines and therapeutic strategies for COVID-19.

Severe fever with thrombocytopenia syndrome (SFTS), first reported in 2012, is a newly emerging tick-borne infectious disease. Although the incidence of SFTSV infection has increased, with a mortality rate of 10%–20%, no effective vaccines are currently available.

Therefore, we characterized the protective immunity to SFTSV, developed a DNA vaccine for SFTSV, and evaluated its immunogenicity and protective efficacy using a lethal infection ferret model. Particularly, we found that ferrets immunized with DNA vaccines exhibited complete protection against a lethal SFTSV challenge, without developing any clinical signs, thus demonstrating the induction of sterilizing immunity (Nature Communications 2019).

Based on these results, we will develop mRNA vaccines against SFTSV with a mRNA vaccine development consortium.

Moreover, we also studied the pathophysiological mechanisms underlying mortality in patients with MERS using clinical samples, which provided insights into the mechanisms by which MERS-CoV causes severe illness/fatal outcomes in humans, as well as the development of prognostic markers for the survival of MERS patients (Thorax 2018)