Research ArticleHEALTH AND MEDICINE

Treating ischemia via recruitment of antigen-specific T cells

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Science Advances  31 Jul 2019:
Vol. 5, no. 7, eaav6313
DOI: 10.1126/sciadv.aav6313
  • Fig. 1 OVA-releasing scaffolds concentrate OVA-specific CD4+T cells following ischemic injury.

    (A) Experimental design using (upper left) OT-II mice (TCR transgenic mice where all CD4+ T cells are OVA specific), (upper right) diagram of scaffold implantation (purple) relative to ischemic upper leg muscles (blue) and ischemic ligation site (red), and (bottom) timeline of experimental procedures. White arrow indicates location of placement of scaffold in the upper right diagram. FACS, fluorescence-activated cell sorting. (B) Instantaneous rate of release in vitro of OVA from PLG scaffolds up to 14 days (n = 3 scaffolds). (C and D) Number of CD4+ T cells (TCR-β+/CD4+ cells) in the (C) scaffold and (D) upper leg muscle per milligram of tissue over time (n = 4 mice). Data are presented as means ± SD. Significance is denoted by *P ≤ 0.05 or ***P ≤ 0.001 with a two-tailed Student’s t test with or without Welch’s correction where applicable.

  • Fig. 2 OVA-releasing scaffolds implanted in vaccinated mice enhance TH2 responses after ischemic injury.

    (A) Experimental setup with (left) BALB/c mice undergoing (right) timeline of procedures involving vaccination and boost with OVA/ALUM, followed by hindlimb ischemia induction and scaffold implantation. (B to J) In these figures, naïve + OVA denotes mice receiving no vaccination and implanted with an OVA-containing scaffold, vacc + blank denotes mice receiving vaccination with OVA/ALUM and a blank scaffold, and vacc + OVA denotes mice receiving vaccination with OVA/ALUM and an OVA-containing scaffold. (B) Number of CD4+ T cells (TCR-β+/CD4+ cells) per milligram of tissue in the ischemic upper leg at days 4 and 7 after ischemic ligation in the various treated groups. (C) Representative images of IL-5 enzyme-linked immunospot (ELISPOT) assay, where cells derived from the ischemic upper leg were cultured in the presence of splenocytes presenting either OVA or CT26-gp70 peptide as an irrelevant peptide control. (D) Quantification of OVA-specific IL-5 spot-forming cells per milligram of tissue determined by subtracting the number of IL-5 spot-forming cells in the CT26-gp70 condition from that in the OVA condition. (E to G) Concentrations of (E) IL-5, (F) IL-10, and (G) IFN-γ produced from OVA-stimulated cells isolated from the ischemic upper leg 7 days after ischemic ligation (n = 6 mice for naïve + OVA; n = 4 mice for vacc + blank; and n = 4 mice for vacc + OVA). (H to J) Number of (H) macrophages (F4/80+ cells), (I) M2a macrophages (F4/80+/CD206+ cells), and (J) eosinophils (Siglec-F+/CD11b+ cells) per milligram of tissue in the ischemic upper leg at days 4 and 7 after ischemic ligation in the various treated groups. For day 4 data in (B) to (D) and (H) to (J), n = 5 mice for naïve + OVA, n = 6 mice for vacc + blank, and n = 6 mice for vacc + OVA. For day 7 data in (B) to (D) and (H) to (J), n = 3 mice for naïve + OVA, n = 6 mice for vacc + blank, and n = 5 mice for vacc + OVA. Data are presented as means ± SD. Significance is denoted by *P ≤ 0.05, **P ≤ 0.01, or ***P ≤ 0.001 by one-way analysis of variance (ANOVA) with Bonferroni’s post hoc test.

  • Fig. 3 Treating vaccinated mice with OVA-releasing scaffolds enhances angiogenesis and muscle regeneration following ischemic injury.

    In this figure, naïve + OVA denotes mice receiving no vaccination and implanted with an OVA-containing scaffold, vacc + blank denotes mice receiving vaccination with OVA/ALUM and a blank scaffold, and vacc + OVA denotes mice receiving vaccination with OVA/ALUM and an OVA-containing scaffold. (A) Ischemic hindlimbs in the various treatment groups were visually examined to determine the severity of hindlimb ischemia at 3, 7, and 14 days after ischemic ligation (n = 10 mice for naïve + OVA, n = 12 mice for vacc + blank, and n = 11 mice for vacc + OVA). (B) Representative histology images and quantification of CD31+ blood vessel densities in ischemic tissue adjacent to scaffold and ligation site in upper leg muscles at 14 days after ischemic ligation (n = 9 mice for naïve + OVA, n = 10 mice for vacc + blank, and n = 9 mice for vacc + OVA). Scale bars, 100 μm. (C) Representative laser Doppler perfusion images and quantification of ischemic to nonischemic blood perfusion ratio in various treated mice over the course of 14 days after ischemic ligation (n = 9 to 10 mice for naïve + OVA, n = 11 to 12 mice for vacc + blank, and n = 10 to 11 mice for vacc + OVA). (D and E) Quantification of percent area of skeletal muscle tissue with (D) ischemic muscle fibers and (E) regenerating muscle fibers in lower leg muscles downstream of the ligation site at 14 days after ischemic ligation (n = 9 mice for naïve + OVA, n = 11 mice for vacc + blank, and n = 10 mice for vacc + OVA). Data are presented as means ± SD. Significance is denoted by *P ≤ 0.05, **P ≤ 0.01, and ***P ≤ 0.001 by one-way ANOVA with Bonferroni’s post hoc test (photo credit: Brian Kwee, Harvard University).

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/5/7/eaav6313/DC1

    Fig. S1. Scaffold implantation on ischemic ligation.

    Fig. S2. Representative FACS gating strategy for quantifying percentage and number of different immune cells.

    Fig. S3. Distribution of CD4+ T cells recruited to scaffold and upper leg muscles.

    Fig. S4. Recruitment of CD4+ T cells in OT-II mice.

    Fig. S5. OVA/ALUM vaccination enhances IL-5–producing OVA-specific CD4+ T cells in BALB/c mice.

    Fig. S6. Concentration of TH2 CD4+ T cells in ischemic hindlimb muscle.

    Fig. S7. Images of wells from IL-5 ELISPOT assay, measuring IL-5–secreting cells from cells isolated from ischemic thighs 4 days after ischemic ligation.

    Fig. S8. Images of wells from IL-5 ELISPOT assay, measuring IL-5–secreting cells from cells isolated from ischemic thighs 7 days after ischemic ligation.

    Fig S9. Concentration of TH1/TH2 cytokines secreted by OVA-stimulated cells in ischemic hindlimb muscle.

    Fig. S10. Distribution of eosinophils recruited to scaffold and upper leg muscles.

    Fig. S11. Presence of α-SMA+ blood vessels in tissue adjacent to scaffold.

    Fig. S12. Antigen-releasing scaffolds enhance blood perfusion recovery following ischemic injury in an antigen-specific manner.

    Fig. S13. Blood perfusion recovery in vaccinated mice with OVA-releasing scaffolds depends on the presence of CD4+ T cells.

    Fig. S14. Characterization of types of muscle fibers in histological sections of ischemic lower leg muscles.

  • Supplementary Materials

    This PDF file includes:

    • Fig. S1. Scaffold implantation on ischemic ligation.
    • Fig. S2. Representative FACS gating strategy for quantifying percentage and number of different immune cells.
    • Fig. S3. Distribution of CD4+ T cells recruited to scaffold and upper leg muscles.
    • Fig. S4. Recruitment of CD4+ T cells in OT-II mice.
    • Fig. S5. OVA/ALUM vaccination enhances IL-5–producing OVA-specific CD4+ T cells in BALB/c mice.
    • Fig. S6. Concentration of TH2 CD4+ T cells in ischemic hindlimb muscle.
    • Fig. S7. Images of wells from IL-5 ELISPOT assay, measuring IL-5–secreting cells from cells isolated from ischemic thighs 4 days after ischemic ligation.
    • Fig. S8. Images of wells from IL-5 ELISPOT assay, measuring IL-5–secreting cells from cells isolated from ischemic thighs 7 days after ischemic ligation.
    • Fig S9. Concentration of TH1/TH2 cytokines secreted by OVA-stimulated cells in ischemic hindlimb muscle.
    • Fig. S10. Distribution of eosinophils recruited to scaffold and upper leg muscles.
    • Fig. S11. Presence of α-SMA+ blood vessels in tissue adjacent to scaffold.
    • Fig. S12. Antigen-releasing scaffolds enhance blood perfusion recovery following ischemic injury in an antigen-specific manner.
    • Fig. S13. Blood perfusion recovery in vaccinated mice with OVA-releasing scaffolds depends on the presence of CD4+ T cells.
    • Fig. S14. Characterization of types of muscle fibers in histological sections of ischemic lower leg muscles.

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