Pe anti mouse cd138

B-cell responses and antigen-specific T-cell responses were determined as described below (Tai et al., 2020 (link)). For T-cell responses, splenocytes (1.0 × 10⁶) were isolated from homogenized spleens of immunized or control mice, and stimulated with overlapping peptides covering the RBD of MERS-CoV (Genscript) for 3 days at 37 °C. Brefeldin A (BioLegend) was added to cells 6 h before staining. After stimulation, the cells were stained with Fixable Viability Dye eFluor 780 (Thermo Fisher Scientific) to distinguish live and dead cells. Cell surface markers were stained with FITC anti-mouse-CD4 and PerCP-Cy5.5 anti-mouse-CD8 antibodies (BioLegend). For intracellular cytokine staining, the cells were fixed and permed using Cytofix/Cytoperm reagent (BD Biosciences), and stained with BV 605 anti-mouse TNF-α, PE anti-mouse IFN-γ, and BV 711 anti-mouse IL-4 antibodies (BioLegend). For B-cell responses, isolated splenocytes were stained with Fixable Viability Dye eFluor 780 to distinguish live and dead cells as described above. The B-cells were then stained with PerCP-Cy5.5 anti-mouse-B220, BV421 anti-mouse-CD27, PE anti-mouse-CD138, and FITC anti-mouse-IgG antibodies (BioLegend). The stained cells were collected using BD LSRFortessa 4 Flow Cytometer. Flow cytometry data were analyzed using FlowJo Software (Tree Star Inc).