Lineage progression from IgM^hi TS B cells through to MZBs. (A) A 3D UMAP plot of CD19⁺ cells from a HCD (10x HCD1, see Fig. S3 C) generated from a PCA run on 2,000 differentially expressed genes. Clusters were merged and pseudocolored according to the B cell subsets they represent as described in Fig. S3 (D–G). (B) CD27 and IgM ADT and CD1C gene signal overlay on the 3D UMAP plot displayed in A. (C) The 3D UMAP plot displayed in A viewed using different UMAP axis coordinates. (D) CD27 and IgM ADT and CD1C gene signal overlay on the 3D UMAP projection in C. (E) A UMAP plot generated by integrating 3 HCD 10x datasets (see Fig. S3 C) and generated from a PCA run on 2,000 variably expressed genes. (F) Feature plots demonstrating overlay of ADT signal on the UMAP plot from E enables identification of clusters representing TS and MZB cells. (G) A Slingshot developmental trajectory overlaid onto the UMAP plot from E demonstrating developmental progression from clusters representing TS B cells to MZBs via IgM^hi naive B cells. (H) A heatmap of selected genes from the top 100 most differentially expressed genes along the Slingshot trajectory demonstrated in G. (I) Feature plots demonstrating overlay of gene signal from the differentially expressed genes along the Slingshot trajectory identified in G.