Fig. 4

B cell application modulates the functional phenotype of infiltrating myeloid immune cells at the site of injury. A Analysis of the differential aggregate cytokine response in cells isolated from the brain of saline-treated and B cell-treated animals showed that the largest overall response at all analyzed time points was observed in the infiltrating CD45^hi immune and inflammatory cells. B Monocytes/macrophages and neutrophils comprise approximately 95% of the CD45^hi infiltrating immune and inflammatory cells. C Temporal dynamics of the relative proportions of CD45^hi cell subsets. In both B cell-treated (continuous lines) and saline-treated (dashed lines) animals, granulocytes declined steadily over time, Ly6C⁺ monocytes/macrophages showed a slight decline and Ly6C⁻ monocyte/macrophages increased substantially up to 2 months post-injury. D–J Analysis of cytokine production in the CD45^hi infiltrating immune cell populations showed a significant impact of B cell treatment, with a complex pattern of immunomodulation. Overall, the proportion of CD45^hi cells expressing high levels of canonical pro-inflammatory cytokines IFNγ, TNFα, and IL-6 was lower in animals treated with B cells (D, F, G). Conversely, more CD45^hi cells expressed high levels of regulatory cytokines IL-10, IL-35, and TGFβ (H, I, J). These regulatory patterns were observed into the chronic stages, at 2 months post-CCI. K The proportion of Ly6C⁺ inflammatory monocytes/ macrophages expressing the M2-associated marker CD206 was significantly increased in B cell-treated animals up to 10 days post-CCI and was still elevated, though trending to baseline levels at 2 months. Overall effects were assessed using 2-way ANOVA, and statistical significance at each timepoint was assessed by multiple two-tailed unpaired t-tests for each individual marker and time point and corrected for multiple comparisons using the Holm-Šídák method. ^#p < 0.1; *p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001