Biology subjects

Sekiya, T.

Publications and source records attributed to Sekiya, T..

3 recordsLinked to original sources

bioRxiv2026

Low-self-reactive, circulation-biased blood regulatory T cells sense danger-associated nucleotides to restrain atherosclerosis

Peripheral blood (PB) is the predominant source of regulatory T cells (Tregs) for clinical applications, yet PB Tregs have not been systematically compared with tissue Tregs and their defining properties remain poorly understood. Here we identify a circulation-biased PB Treg population with reduced self-reactivity. Although PB Tregs are less suppressive in vitro, they are hypersensitive to the danger-associated nucleotides ATP and NAD+, linked to a high ARTC2.2/CD38 ratio. ATP/NAD+-triggered apoptotic conversion of PB Tregs promotes macrophage efferocytosis and selectively dampens IFN-{gamma}-driven inflammatory polarization while preserving IL-10-associated programs and enhancing the scavenger receptor Mertk, suggesting that efferocytosis-mediated macrophage reprogramming contributes to lesion control. Consistent with this model, in atherosclerosis-prone mice lacking T cells, PB Treg transfer effectively limits plaque growth and necrotic core formation. We identify an ATP/NAD+-hypersensitive PB Treg fraction in both mice and humans and provide evidence consistent with preferential efferocytosis of this subset within atherosclerotic plaques.

immunology↗

bioRxiv2020

Potent mouse monoclonal antibodies that block SARS-CoV-2 infection

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has developed into a global pandemic since its first outbreak in the winter of 2019. An extensive investigation of SARS-CoV-2 is critical for disease control. Various recombinant monoclonal antibodies of human origin that neutralize SARS-CoV-2 infection have been isolated from convalescent patients and will be applied as therapies and prophylaxis. However, the need for dedicated monoclonal antibodies in molecular pathology research is not fully addressed. Here, we produced mouse anti-SARS-CoV-2 spike monoclonal antibodies that exhibit not only robust performance in immunoassays including western blotting, ELISA, immunofluorescence, and immunoprecipitation, but also neutralizing activity against SARS-CoV-2 infection in vitro. Our monoclonal antibodies are of mouse origin, making them compatible with the experimental immunoassay setups commonly used in basic molecular biology research laboratories, and large-scale production and easy distribution are guaranteed by conventional mouse hybridoma technology.

microbiology↗

bioRxiv2020

Development of Microsatellite Markers for a Soricid Water Shrew Chimarrogale platycephalus, and the Success of Individual Identification Using It.

The soricid water shrew, Chimarrogale platycephalus, is a mammal species endemic to the Japanese Islands. They inhabit the islands of Honshu and Kyushu, and are considered to be extinct in Shikoku. Information on this water shrew from Honshu and Kyushu is also scarce, and C. platycephalus is registered on the Japanese Governments red list as an endangered species. Almost all study areas such as regarding their ethology, ecology, also their phylogenetics are lacking. The delay in these foundational studies is due to difficulties related to them being both nocturnal and aquatic. In order to study of C. platycephalus, it is essential to conduct field research in mountain streams at night under such circumstances. In response to such difficult circumstances, we established a genetic analysis method using the feces of C. platycephalus, and as a result the accumulation of data on their phylogenetic evolution and phylogeography has increased which has improved our understanding of this species. Furthermore in this study, development of microsatellite markers was carried out, and a total of 21 loci marker analyses were performed. In addition, in order to confirm the credibility of these 21 microsatellite markers, as being able to validly differentiate individuals, all markers were examined using the fecal and tissues specimens from verified separately reared individuals (12 individuals) with the known history of having been reared in an aquarium. As a result, it was revealed that if analyses of the 12 loci were possible, individual differentiation with 100% accuracy was possible. The development of microsatellite markers in this study, and the establishment of individual identification methods by means of this will be expected to greatly contribute to future ecological and ethological research, population genetics and biogeographical research of the water shrew, C. platycephalus.

evolutionary biology↗