Fig 2: Abnormal Splenic B Cell Differentiation and B Cell Response in Mice Lacking MTA2 or Both MTA2 and OCA-B(A) Staining of total splenic B (B220+), marginal zone B (MZB) (B220+CD21hiCD23lo), and follicular B (FOB) (B220+CD21-CD23hi) cells in Vav-Cre Mta2fl/fl and control mice. Frequencies of different cell populations in parental cells are indicated.(B) Staining of germinal center B (GCB) (B220+CD95+CD38-CD4-) cells in Vav-Cre Mta2fl/fl and control mice immunized by sheep red blood cells (SRBCs).(C) Numbers of GCB cells and frequencies of GCB cells in splenic B cells are plotted (n = 8 for each genotype; t test; *p = 0.02).(D) Staining of splenic B, MZB, and FOB cells in mice with indicated genotypes.(E) Cell numbers of different B cell subsets are plotted (n = 10 for control, n = 9 for Vav-Cre Mta2fl/fl, n = 5 for Oca-B-/- and DKO mice; t test; *p < 0.05, **p < 0.01, ***p < 0.001).

Fig 3: (A) Structure of p(GluNAc) conjugated to an antigen lysyl side chain amine via a self-immolative linker. (B, C) Accumulation of OVA647 or OVA647-p(GluNAc) in the dLNs and livers 15 h after s.c. or i.v. injection. (B) Representative NIR images of dLNs and liver. (C) Average NIR intensities of dLNs and livers. (D, E) Mice were injected with saline or 5 µg of OVA647 or OVA647-p(GluNAc) s.c. and the draining popliteal LNs were isolated and imaged at various timepoints between 1-72 h post-injection n (dLN)= 2 for saline and 4 for OVA647 or OVA647-p(GluNAc) at each timepoint. (D) Representative NIR images of dLNs. (E) Quantification of OVA accumulation in dLNs, expressed as µg (left) or % of initial injected dose (right). (F, G) Flow cytometry analysis of LN cells that took up OVA647-p(GluNAc) 15 h after s.c. injection of 20 µg of OVA647-p(GluNAc). DC, dendritic cell; pDC, plasmacytoid dendritic cell; MAC, macrophage; SCS, subcapsular sinus; med, medullary; TZ MAC, T cell zone macrophage; LEC, lymphatic endothelial cell (CD45-CD31+gp38+); BEC, blood endothelial cell (CD45-CD31+gp38-); FRC, fibroblastic reticular cell (CD45-CD31-gp38+CD21/35-); FDC, follicular dendritic cell (CD45-CD31-gp38+CD21/35+); DNSC, double negative stromal cell (CD45-CD31-gp38-). (F) Percent of each cell subset that is OVA+. (G) OVA647 MFI of each OVA+ cell subset. (H–J) Representative whole mount confocal images of immunostained dLNs after s.c. injection of OVA647-p(GluNAc) (red). (H) LNs stained versus CD11c (green), CD11b (blue) and Collagen IV (white), 8 h post-injection (p.i.). CD11c+CD11b+ DCs are shown in aqua and co-localized OVA-p(GluNAc) is shown in magenta. Scale bar ranges from 20-100 µm and is indicated in each panel. (I) LNs stained versus CD11c (green) and CD8 (blue) 18 h p.i. CD11c+CD8+ double positive DCs are shown in aqua and co-localized OVA-p(GluNAc) is shown in magenta. Scale bar ranges from 5-50 µm and is indicated in each panel. (J) LNs stained versus CD169 (green, top) and Lyve1 (blue, bottom). Co-localized OVA-p(GluNAc) with CD169+ macrophages is shown in yellow (top), and OVA-p(GluNAc) co-localized with the lymphatics is shown in magenta (bottom). Scale bar ranges from 5-50 µm and is indicated in each panel. Data represent mean ± SD. *p = 0.05, **p = 0.01, ***p = 0.001, ns is not significant by one-way ANOVA using Tukey’s post hoc test in (C), and two-way ANOVA using Sidak’s post hoc test in (E).