Fig. 3

L. reuteri expands the GC-like B cell population and reprograms its functional gene signature. a, c Immunohistochemistry of the GL7⁺ area stained with anti-B220 (magenta), anti-GL7 (green) and anti-Ki67 (cyan). Scale bars equal 100 μm. Representative images of PPs from the control or L. reuteri-treatment are shown in a and c, and the corresponding quantification shown in Fig. S3G, H. b, d Flow cytometry quantification of GL7⁺ B cells (in CD3⁻CD19⁺B220⁺, n = 5–6 mice per group) and Ki67⁺ cells (n = 5–6 mice per group). e In vivo proliferation assay was performed by flow cytometry following i.p. injection of EdU. A histogram depicting EdU expression in GL7⁻, GL7⁺ or EdU⁺CD19⁺B220⁺B cells and the number of EdU⁺GL7⁺ B cells (n = 6 mice per group). f Expression of Mki67, Gsk-3α, and Hif-1α in large GC-like B cells from control or L. reuteri-treated mice (GOI, gene of interest; A.U., arbitrary unit). g q-RT-PCR analysis of gene expression levels (n = 6 mice per group) and expression of TGFβR1 (microarray analysis). h Flow cytometry analyzing the numbers of TGFβ1⁺ B cells as well as the TGFβ1 levels (MFI, n = 6–18 mice per group). i The PPs tissue was analyzed for cytokine/chemokine production by Multi-Plex Mesoscale and ELISA, normalized to tissue protein content (n = 6 mice per group). j Expression of α germline transcripts (αGT) in PPs (n = 6 mice per group). k The numbers of B cells of different subsets in PPs in untreated mice and in response to L. reuteri R2LC and L. reuteri R2LC_ΔADO (n = 6 mice per group). Data are presented as mean ± SEM. *p < 0.05, **p < 0.01 using Student’s t test or ANOVA with Tukey’s post hoc test