Two distinct subpopulations of marginal zone B cells exhibit differential antibody-producing capacities and radioresistance.

Marginal zone (MZ) B cells, which are splenic innate-like B cells that rapidly secrete antibodies (Abs) against blood-borne pathogens, are composed of heterogeneous subpopulations. Here, we showed that MZ B cells can be divided into two distinct subpopulations according to their CD80 expression levels. CD80high MZ B cells exhibited greater Ab-producing, proliferative, and IL-10-secreting capacities than did CD80low MZ B cells. Notably, CD80high MZ B cells survived 2-Gy whole-body irradiation, whereas CD80low MZ B cells were depleted by irradiation and then repleted with one month after irradiation. Depletion of CD80low MZ B cells led to accelerated development of type II collagen (CII)-induced arthritis upon immunization with bovine CII. CD80high MZ B cells exhibited higher expression of genes involved in proliferation, plasma cell differentiation, and the antioxidant response. CD80high MZ B cells expressed more autoreactive B cell receptors (BCRs) that recognized double-stranded DNA or CII, expressed more immunoglobulin heavy chain sequences with shorter complementarity-determining region 3 sequences, and included more clonotypes with no N-nucleotides or with B-1a BCR sequences than CD80low MZ B cells. Adoptive transfer experiments showed that CD21+CD23+ transitional 2 MZ precursors preferentially generated CD80low MZ B cells and that a proportion of CD80low MZ B cells were converted into CD80high MZ B cells; in contrast, CD80high MZ B cells stably remained CD80high MZ B cells. In summary, MZ B cells can be divided into two subpopulations according to their CD80 expression levels, Ab-producing capacity, radioresistance, and autoreactivity, and these findings may suggest a hierarchical composition of MZ B cells with differential stability and BCR specificity.

Alteration of γδ T cell subsets in non-human primates transplanted with GGTA1 gene-deficient porcine blood vessels.

BACKGROUND: αGal-deficient xenografts are protected from hyperacute rejection during xenotransplantation but are still rejected more rapidly than allografts. Despite studies showing the roles of non-Gal antibodies and αß T cells in xenograft rejection, the involvement of γδ T cells in xenograft rejection has been limitedly investigated. METHODS: Six male cynomolgus monkeys were transplanted with porcine vessel xenografts from wild-type (n = 3) or GGTA1 knockout (n = 3) pigs. We measured the proportions and T cell receptor (TCR) repertoires of blood γδ T cells before and after xenotransplant. Grafted porcine vessel-infiltrating immune cells were visualized at the end of experiments. RESULTS: Blood γδ T cells expanded and infiltrated into the graft vessel adventitia following xenotransplantation of α-Gal-deficient pig blood vessels. Pre- and post-transplant analysis of γδ TCR repertoire revealed a transition in δ chain usage post-transplantation, with the expansion of several clonotypes of δ1, δ3, or δ7 chains. Furthermore, the distinctions between pre- and post-transplant δ chain usages were more prominent than those observed for γ chain usages. CONCLUSION: γδ TCR repertoire was significantly altered by xenotransplantation, suggesting the role of γδ T cells in sustained xenoreactive immune responses.

The emergence of remote laboratory courses in an emergency situation: University instructors' agency during the COVID-19 pandemic.

This study examines and describes how various online remote laboratory courses, necessitated by the COVID-19 pandemic, were implemented at Hankuk University in Korea in 2020. We compared four general undergraduate laboratory courses, one each for physics, chemistry, biology, and earth science, and two major-level laboratory courses taught during the spring and fall of 2020. Employing a sociocultural perspective, we examined how the changes in structures at the macro-, meso-, and micro-levels shaped the responses of educational authorities and impacted the agency of university instructors. Instructors implemented various remote laboratory courses in each content area dependent upon availability and access to material resources, including access to video of laboratory activities, and also based on the nature of experimental data associated with each content area. Drawing from survey responses and in-depth interviews with instructors and students, we share findings about how instructor practices impacted the interactions of students, the processes for evaluation, and student learning. We discuss how the global pandemic has re-ignited the debate about the role and value of experimental laboratory activities for undergraduate science majors and about the significance of hands-on versus minds-on science learning. Implications for how universities approach laboratory coursework in the post-COVID-19 are discussed, and questions for university science instruction are raised for future research.

Amperometric Glucose Biosensor Utilizing Zinc Oxide-chitosan-glucose Oxidase Hybrid Composite Films on Electrodeposited Pt-Fe(III).

We developed an amperometric glucose biosensor based on glucose oxidase (GOx) embedded in zinc oxide (ZnO)-chitosan (CS) hybrid composite films on electrodeposited Pt-Fe(III). This sensor exhibited a fast amperometric response (less than 10 s) to glucose, linearity from 10 µM to 11.0 mM of glucose with a detection limit of 1.0 µM (S/N = 3) and sensitivity of 30.70 µA mM-1 cm-2. An apparent Michaelis-Menten constant of 5.19 mM indicated high affinity between glucose and GOx immobilized in the ZnO-CS films. The effect of interferences such as uric acid, ascorbic acid, and acetaminophen on the performance of this sensor was negligible. In addition, this sensor retained 87% of its initial performance after two weeks of storage at 4°C, indicating that the hybrid composite films allowed successful immobilization of GOx with its high enzymatic activity.