Fig. 6: Crosstalk between Cd138⁺ plasma cells and homeostatic microglia in the brain of chronically infected animals.

A Circos plot of significant ligand-receptor interactions between Cd138⁺ plasma cells and HM 1 (light blue), HM 2 (dark blue), and Mrc1⁺ BAMs (purple). Redundant interactions (shared by >1 cell type) are shown in light green. B Heatmap of the most significant ligand-receptor interactions between Cd138⁺ plasma cells and microglia. C Dot Plot representing the expression level of Tnfsf13b (BAFF) and its cognate receptor Tnfrsf17 (BCMA). D Dot Plot representing the expression level of Tnfsf13b (BAFF) in the various microglia subsets identified in the mouse hypothalamus during T. brucei infection. E Predicted spatial ligand-receptor interaction analysis for Tnfsf13b-Tnfrsf17 in the mouse brain at 45dpi. The relative expression level is indicated, and colour coded. F Chronic T. brucei infection induces the expression of Tnfsf13b and Tnrsf17 in homeostatic microglia and B cells, respectively. Representative smFISH probe targeting Cx3cr1 (purple), Cd79a (green), Tnfsf13b (red), and Tnfrsf17 (orange) around the lateral ventricle (LV) in an infected mouse brain coronal section. Cx3cr1 was chosen as a marker for homeostatic microglia. Scale, 25 μm. The results presented here are representative from two independent experiments. G Representative flow cytometry analysis and quantification of BAFF⁺ microglia in naïve and infected animals (30 dpi) using flow cytometry (n = 3 naïve or 4 infected mice from a single replicate). Data are presented as mean values+/− SD. Pairwise comparison was conducted against naïve samples using a parametric T test. p < 0.05 is considered significant. **p < 0.005.