2026年 4月 Student Monthly Progress を開催しました

4月24日 (金)にStudent Monthly Progressが開催されました。4名の大学院生が研究内容について発表しました。

 

【Presenters】

  1.  Khesara Sastrin Prasita Negara : Division of Collaboration and Education

  <Analysis of the molecular basis of host specificity of Babesia bovis using an artificial evolutionary approach>

 

  2. Joseph Ndebe : Division of International Research Promotion

  <Characterization of a novel bandavirus in Egyptian fruits bats in Zambia>

 

3. Hexelsa Joy C. Nunez : Laboratory of Theriogenology

  <Exploring the role of immune cells in the OPN peptide-modulated endometrial function>

 

4. Toda Masahiro : Division of Global Epidemiology

<Generation and characterization of anti-Sudan virus antibodies>

 

【Chairs】

Kwadwo Yeboah BOATENG : Division of International Research Promotion

Yoshinosuke MOTAI : Laboratory of Infectious Diseases

 

 

 

 ❖座長レポート❖ 

 

《Analysis of the molecular basis of host specificity of Babesia bovis using an artificial evolutionary approach》

Khesara Sastrin Prasita Negara

 

 

 

Babesia bovis had been considered non-zoonotic because it specifically infected bovine red blood cells (RBCs), but prior in vitro findings showed that it could adapt to human RBCs, raising concerns about zoonotic potential. Based on this, the study used ENU mutagenesis to explore whether specific mutations enabled this adaptation. The researchers compared growth, invasion, and replication of parent and adapted parasites in bovine and human RBCs. They found that while parent parasites grew only in bovine RBCs, adapted parasites grew in both cell types. Invasion and replication of parent parasites were significantly reduced in human RBCs, indicating that both processes acted as barriers to infection. In contrast, adapted parasites showed similar invasion and replication efficiencies in bovine and human RBCs. Overall, the findings suggested that successful adaptation to human RBCs required overcoming limitations in both invasion and replication. 

 

 

《Characterization of a novel bandavirus in Egyptian fruits bats in Zambia》

Joseph Ndebe 

 

 

 

Severe fever with thrombocytopenia syndrome virus (SFTSV), a tick-borne bandavirus endemic to East Asia, had been recognized as a high-fatality pathogen, while related viruses were increasingly detected outside endemic regions, including in bats. However, the origin and ecological role of bat-associated bandaviruses remained unclear. This study isolated and characterized a novel bat-derived bandavirus, named Suesueman virus (SUEV), and assessed its pathogenic and zoonotic potential. A total of 224 bats were sampled, and one sample showed cytopathic effects. Viral isolation was confirmed by electron microscopy, and metagenomic sequencing recovered the complete genome. Phylogenetic and sequence analyses indicated that SUEV was closely related to Malsoor virus but represented a distinct species. Although key functional motifs were conserved, some substitutions associated with virulence were identified. In vitro, SUEV showed higher infectivity in human cell lines than in bat cells. In vivo, it was non-pathogenic in immunocompetent mice but caused disease in immunocompromised mice, with the spleen, liver, and kidneys identified as major target organs. Microneutralization assays suggested possible human exposure. Overall, SUEV was identified as a novel bandavirus with distinct genetic and biological features, and its ability to infect human cells and evidence of human exposure indicated a potential zoonotic risk. 

 

 

 《Exploring the role of immune cells in the OPN peptide-modulated endometrial function》

 Hexelsa Joy C. Nunez 

 

 

 

Reproductive performance in dairy cows had declined alongside increasing milk yield, negatively affecting both animal health and the industry. An osteopontin-derived peptide (OPN peptide) had previously been shown to improve fertility by restoring the endometrial epidermal growth factor (EGF) profile, but its mechanism of action remained unclear. This study aimed to investigate whether the OPN peptide stimulated pro-inflammatory cytokine expression in peripheral blood mononuclear cells (PBMCs) and how this might relate to endometrial function. PBMCs from synchronized, reproductively healthy cows were isolated, cultured, and treated with or without the OPN peptide. Cytokine gene expression (IL1B, IL8, TNF-α) was measured after 2 and 4 hours, with LPS as a positive control. IL1B expression was unaffected by treatment or time. IL8 expression increased at 4 hours, but this was independent of OPN peptide treatment. In contrast, TNF-α expression was significantly influenced by both treatment and time, with higher levels observed in OPN-treated cells at 2 hours. No interaction between treatment and time was detected. Overall, the results suggested that OPN peptide exposure partially activated PBMCs and induced cytokine expression. However, as the findings were limited to PBMC responses, further studies were needed to determine the peptide’s effects on endometrial function and EGF production. 

 

 

《Generation and characterization of anti-Sudan virus antibodies》

Toda Masahiro 

 

 

 

Sudan virus (SUDV), a cause of Ebola virus disease with increasing outbreak frequency, lacked effective approved antibody treatments. In this study, monoclonal antibodies (mAbs) against SUDV were generated and characterized for their neutralizing activity, cross-reactivity, epitopes, and mechanisms of action. BALB/c mice were immunized with SUDV GP–pseudotyped virus, and hybridomas were produced to isolate mAbs. Neutralization assays using pseudotyped orthoebolaviruses, escape mutant analysis, and competitive ELISA for NPC1 binding were conducted. A total of 14 mAb clones were identified, some of which showed cross-neutralizing activity against multiple orthoebolaviruses. The antibodies targeted diverse epitopes, including the GP base, GP2 N-terminus with heptad repeat 1, glycan cap/head, NPC1 binding site, and heptad repeat2 with the membrane-proximal external region. Several mAbs also inhibited GP–NPC1interaction. Overall, the generated mAbs demonstrated neutralizing activity againstSUDV and related viruses, revealing diverse mechanisms of action and highlighting theirpotential as therapeutic candidates.