Fig 2: Transcutaneous arginase inhibition is associated with significantly more intratumoral T cells and dendritic cells in PDVC57 tumors. (A) Percentage of intratumoral CD45+ leukocytes that are CD3+ CD4+, CD3+ CD8+, or CD3+ PD-1+ indicating tumor-infiltrating T cells; CD3+ CD4+, CD3+ CD8+, CD3+ PD-1+ cells significantly higher in nor-NOHA-treated tumors. (B) Percentage of intratumoral CD45+ leukocytes that are CD11c+ MHCII+, indicating tumor-infiltrating dendritic cells; significantly higher in nor-NOHA-treated tumors. **P < 0.01; ***P < 0.001 using the unpaired t-test adjusted for multiple comparisons. Two separate experiments with n > 5 per group.

Fig 3: PDVC57 tumors recruit more tumor-associated macrophages and fewer T cells and dendritic cells than PDV tumors. (A) Percentage of intratumoral CD45+ leukocytes that are CD11b+ F4/80+, indicating tumor-associated macrophages; significantly higher in PDVC57 tumors. (B) Percentage of intratumoral CD45 + leukocytes that are CD3+ CD4+ or CD3+ CD8+, indicating tumor-infiltrating T cells; CD3+ CD4+, CD3+ CD8+ cells significantly lower in PDVC57 tumors. (C) Percentage of intratumoral CD45+ leukocytes that are CD11c+ MHCII+, indicating tumor-infiltrating dendritic cells; significantly lower in PDVC57 tumors. (D) Arginase activity in units of catalytic activity (U) as assessed by enzymatic fluorometric assay; significantly higher in PDVC57 tumors. *P < 0.05; **P < 0.01; ***P < 0.001 using the unpaired t-test adjusted for multiple comparisons. Two separate experiments with n > 5 per group.

Fig 4: Foe-TEVs attenuated excessive allosensitization kinetics in secondary lymphoid organ. A) Schematic diagram revealing the administration of EVs in sham, isograft, Vector-TEVs, Foe-TEVs, and FK506 groups. B) MFI detection of total DSA levels in serum at day 0, day 7, day 21, day 42, and day 56 post-transplant, respectively (n = 6). C) Kinetics of allospecific T cell responses 7 days post-transplant (n = 6). D) Kinetics of allospecific T cell responses 21 days post-transplant (n = 6). E) immunofluorescence staining of GL7+ GCs located within the follicle (B220+) in spleen at 7 days and 21 days post-transplant, respectively. F) Gating strategy for isolating GL7+ FAS+ GCB cells, CD138+ SPPCs, and CD4+ Th cells. G) The quantitative statistics of GL7+ germinal centers in E) at day 7 and day 21 post-transplant (n = 8). H–J) The quantitative statistics of GL7+ FAS+ GCB cells (H), CD138+ SPPCs (I), and CD4+ Th cells (J) at day 7 and day 21 post-transplant respectively (n = 8). DSA, donor specific antibody; GC, germinal center; SPPC, splenic plasma cell; n.s., not significant, ***P < 0.001, ###P < 0.001 compared with the Foe-TEVs group. Values are presented as mean ± SEM. Statistical analysis was determined by two-tailed Student's t-test.

Fig 5: Magnitude of regulation of IgG1+ B cells by NKT cells varies by mouse facility, but is dependent on CD1d Stool collected from C57BL/6 and CD1d-/- mice was analyzed by ELISA for IgG1 as described in Fig 3. Mice were age- and sex-matched and housed in the Longwood Center facility. C57BL/6 n = 18; CD1d-/- n = 5. Mann–Whitney test. Error bars are SD.Spleen, mLN, and PP cells were harvested from wild-type or CD1d-/- mice, stained with antibodies to B220 and IgG1, and analyzed by flow cytometry. Mice were age- and sex-matched and housed in the Longwood Center facility. C57BL/6 n = 5; CD1d-/- n = 3. Mann–Whitney test. Error bars are SD.Analysis was performed identically to that shown in Fig 3F, except that mice were housed in the Smith Building at Dana-Farber Cancer Institute prior to moving to the Longwood Center at Dana-Farber Cancer Institute. Results in Fig 3 are entirely from mice housed in the Longwood Center facility. C57BL/6 n = 10; Va14-/- n = 12; Ja18-/- n = 3. Mann–Whitney test. Error bars are SD.Culture supernatants from Fig 5D and E were measured by ELISA for IgM. np = not performed. Mann–Whitney test. Error bars are SD.