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Partial depletion of regulatory T cells does not influence the inflammation caused by high dose hemi-body irradiation.

Ma S, Richardson JA, Bitmansour A, Solberg TD, Pidikiti R, Song K, Stojadinovic S, Vitetta ES, Meyer JJ - PLoS ONE (2013)

Bottom Line: HBI significantly decreased the leukocyte pool though the various leukocyte subsets had different sensitivities to HBI.The administration of PC61 significantly decreased the proportion of Treg cells in spleen, iLN, mLN and blood (reduction of approximately 60%).The same general patterns were observed whether or not Treg cells were partially depleted with PC61 prior to HBI.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America.

ABSTRACT
There is clinical interest in the modulation of regulatory T cells for cancer therapy. The safety of these therapies in combination with conventional anti-cancer therapies, including radiation therapy, can be studied in animal models. The effects of partial depletion of regulatory T (Treg) cells with an anti-CD25 antibody in conjunction with ionizing radiation on inflammation and tissue injury were analyzed in C57BL/6 mice. An anti-CD25 antibody (PC61) was administered 3 days prior to 13 Gy lower-half hemi-body irradiation (HBI). The blood, spleen, mesenteric lymph nodes (mLNs) and inguinal lymph nodes (iLNs) were harvested at various times thereafter. Alterations in the proportion of leukocyte subsets including CD4(+) T cells, CD8(+) T cells, Treg cells, B cells, NK cells, NK1.1(+) T cells, macrophages and granulocytes were analyzed by FACS. The lungs, liver, pancreas, stomach, jejunum, duodenum, ileum, colon and kidney were harvested and studied by H&E staining. Expression of inflammatory mediators in plasma and tissue were investigated by ELISA. HBI significantly decreased the leukocyte pool though the various leukocyte subsets had different sensitivities to HBI. The administration of PC61 significantly decreased the proportion of Treg cells in spleen, iLN, mLN and blood (reduction of approximately 60%). Irradiation significantly increased the proportion of Treg cells in the spleen, iLN and mLN. HBI induced a systemic inflammatory reaction as demonstrated by increased plasma levels of IL-6, KC/CXCL1 and circulating granulocytes in the blood. Neutrophils also infiltrated the small bowel. The same general patterns were observed whether or not Treg cells were partially depleted with PC61 prior to HBI. These data demonstrate that partial depletion of Treg cells in these mice does not influence HBI-induced inflammatory response and tissue injury, and that combining anti-CD25 therapy with radiation may be safe and well tolerated in a clinical setting.

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The proportion of CD4+FoxP3+ cells in the spleens, LNs and peripheral blood.(A) The proportion of CD4+FoxP3+ Treg cells and (B) the proportion of CD4+CD25+ cells. PC61 administration reduced the proportion of CD4+FoxP3+ Treg cells and CD4+CD25+ cells in spleen, iLN, mLN and blood, irradiation increased their proportion in spleen, iLN, and mLN but not in blood. Data are shown as Mean±SD (n = 4). Two way ANOVA showed significant interactions over time between treatments in the proportion of CD4+FoxP3+ Treg cells and in the proportion of CD4+CD25+ cells in all compartments (all p<0.01). Differences between all pairs (PC61+sham irradiation vs Rat IgG+sham irradiation, PC61+irradiation vs PC61+sham irradiation, Rat IgG+sham irradiation compare to Rat IgG+irradiation, Rat IgG+sham irradiation compare to PC61+irradiation, PC61+sham irradiation compared to Rat IgG+irradiation and PC61+sham irradiation compared to PC61+irradiation treatment groups) of treatment group profiles over time were significant (p<0.05) except the proportion of Treg cells between PC61+sham irradiation vs PC61+irradiation in blood (p = 0.948), and the proportion of CD4+CD25+ cells between PC61+sham irradiation vs PC61+irradiation in all compartments (p≥0.105). All post hoc pairwise comparisons were performed with Tukey's multiple comparisons. This is one representative experiment of three performed.
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pone-0056607-g004: The proportion of CD4+FoxP3+ cells in the spleens, LNs and peripheral blood.(A) The proportion of CD4+FoxP3+ Treg cells and (B) the proportion of CD4+CD25+ cells. PC61 administration reduced the proportion of CD4+FoxP3+ Treg cells and CD4+CD25+ cells in spleen, iLN, mLN and blood, irradiation increased their proportion in spleen, iLN, and mLN but not in blood. Data are shown as Mean±SD (n = 4). Two way ANOVA showed significant interactions over time between treatments in the proportion of CD4+FoxP3+ Treg cells and in the proportion of CD4+CD25+ cells in all compartments (all p<0.01). Differences between all pairs (PC61+sham irradiation vs Rat IgG+sham irradiation, PC61+irradiation vs PC61+sham irradiation, Rat IgG+sham irradiation compare to Rat IgG+irradiation, Rat IgG+sham irradiation compare to PC61+irradiation, PC61+sham irradiation compared to Rat IgG+irradiation and PC61+sham irradiation compared to PC61+irradiation treatment groups) of treatment group profiles over time were significant (p<0.05) except the proportion of Treg cells between PC61+sham irradiation vs PC61+irradiation in blood (p = 0.948), and the proportion of CD4+CD25+ cells between PC61+sham irradiation vs PC61+irradiation in all compartments (p≥0.105). All post hoc pairwise comparisons were performed with Tukey's multiple comparisons. This is one representative experiment of three performed.

Mentions: To characterize the effect of radiation on Treg cells, the proportion of CD4+FoxP3+ cells within the total CD4+ cell population was evaluated following HBI+/−treatment with PC61. As expected, the administration of PC61 significantly decreased the proportion of Treg cells in spleen, iLN, mLN and blood, although this depletion was incomplete (Figure 4). Depletion of Treg cells with PC61 alone reached its nadir on day 7 with a relative reduction of ∼60%. Compared to sham irradiation, irradiation alone caused a significant increase in the proportion of Treg cells in the spleen, iLN and mLN, and a decrease in their proportion in the blood at 4 hrs, and 1 and 3 days. PC61+HBI treatment resulted in an increase in the proportion of Treg cells in the spleen, as compared with PC61+sham irradiation treatment. However, the proportion of Treg cells in mice treated with PC61+HBI was significantly lower than that of the mice receiving Rat IgG+HBI. Overall, the changes in the proportion of the CD4+CD25+ subset within the CD4+ cell population were similar to those of CD4+FoxP3+ cells (Figure 4).


Partial depletion of regulatory T cells does not influence the inflammation caused by high dose hemi-body irradiation.

Ma S, Richardson JA, Bitmansour A, Solberg TD, Pidikiti R, Song K, Stojadinovic S, Vitetta ES, Meyer JJ - PLoS ONE (2013)

The proportion of CD4+FoxP3+ cells in the spleens, LNs and peripheral blood.(A) The proportion of CD4+FoxP3+ Treg cells and (B) the proportion of CD4+CD25+ cells. PC61 administration reduced the proportion of CD4+FoxP3+ Treg cells and CD4+CD25+ cells in spleen, iLN, mLN and blood, irradiation increased their proportion in spleen, iLN, and mLN but not in blood. Data are shown as Mean±SD (n = 4). Two way ANOVA showed significant interactions over time between treatments in the proportion of CD4+FoxP3+ Treg cells and in the proportion of CD4+CD25+ cells in all compartments (all p<0.01). Differences between all pairs (PC61+sham irradiation vs Rat IgG+sham irradiation, PC61+irradiation vs PC61+sham irradiation, Rat IgG+sham irradiation compare to Rat IgG+irradiation, Rat IgG+sham irradiation compare to PC61+irradiation, PC61+sham irradiation compared to Rat IgG+irradiation and PC61+sham irradiation compared to PC61+irradiation treatment groups) of treatment group profiles over time were significant (p<0.05) except the proportion of Treg cells between PC61+sham irradiation vs PC61+irradiation in blood (p = 0.948), and the proportion of CD4+CD25+ cells between PC61+sham irradiation vs PC61+irradiation in all compartments (p≥0.105). All post hoc pairwise comparisons were performed with Tukey's multiple comparisons. This is one representative experiment of three performed.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC3569437&req=5

pone-0056607-g004: The proportion of CD4+FoxP3+ cells in the spleens, LNs and peripheral blood.(A) The proportion of CD4+FoxP3+ Treg cells and (B) the proportion of CD4+CD25+ cells. PC61 administration reduced the proportion of CD4+FoxP3+ Treg cells and CD4+CD25+ cells in spleen, iLN, mLN and blood, irradiation increased their proportion in spleen, iLN, and mLN but not in blood. Data are shown as Mean±SD (n = 4). Two way ANOVA showed significant interactions over time between treatments in the proportion of CD4+FoxP3+ Treg cells and in the proportion of CD4+CD25+ cells in all compartments (all p<0.01). Differences between all pairs (PC61+sham irradiation vs Rat IgG+sham irradiation, PC61+irradiation vs PC61+sham irradiation, Rat IgG+sham irradiation compare to Rat IgG+irradiation, Rat IgG+sham irradiation compare to PC61+irradiation, PC61+sham irradiation compared to Rat IgG+irradiation and PC61+sham irradiation compared to PC61+irradiation treatment groups) of treatment group profiles over time were significant (p<0.05) except the proportion of Treg cells between PC61+sham irradiation vs PC61+irradiation in blood (p = 0.948), and the proportion of CD4+CD25+ cells between PC61+sham irradiation vs PC61+irradiation in all compartments (p≥0.105). All post hoc pairwise comparisons were performed with Tukey's multiple comparisons. This is one representative experiment of three performed.
Mentions: To characterize the effect of radiation on Treg cells, the proportion of CD4+FoxP3+ cells within the total CD4+ cell population was evaluated following HBI+/−treatment with PC61. As expected, the administration of PC61 significantly decreased the proportion of Treg cells in spleen, iLN, mLN and blood, although this depletion was incomplete (Figure 4). Depletion of Treg cells with PC61 alone reached its nadir on day 7 with a relative reduction of ∼60%. Compared to sham irradiation, irradiation alone caused a significant increase in the proportion of Treg cells in the spleen, iLN and mLN, and a decrease in their proportion in the blood at 4 hrs, and 1 and 3 days. PC61+HBI treatment resulted in an increase in the proportion of Treg cells in the spleen, as compared with PC61+sham irradiation treatment. However, the proportion of Treg cells in mice treated with PC61+HBI was significantly lower than that of the mice receiving Rat IgG+HBI. Overall, the changes in the proportion of the CD4+CD25+ subset within the CD4+ cell population were similar to those of CD4+FoxP3+ cells (Figure 4).

Bottom Line: HBI significantly decreased the leukocyte pool though the various leukocyte subsets had different sensitivities to HBI.The administration of PC61 significantly decreased the proportion of Treg cells in spleen, iLN, mLN and blood (reduction of approximately 60%).The same general patterns were observed whether or not Treg cells were partially depleted with PC61 prior to HBI.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiation Oncology, The University of Texas Southwestern Medical Center, Dallas, Texas, United States of America.

ABSTRACT
There is clinical interest in the modulation of regulatory T cells for cancer therapy. The safety of these therapies in combination with conventional anti-cancer therapies, including radiation therapy, can be studied in animal models. The effects of partial depletion of regulatory T (Treg) cells with an anti-CD25 antibody in conjunction with ionizing radiation on inflammation and tissue injury were analyzed in C57BL/6 mice. An anti-CD25 antibody (PC61) was administered 3 days prior to 13 Gy lower-half hemi-body irradiation (HBI). The blood, spleen, mesenteric lymph nodes (mLNs) and inguinal lymph nodes (iLNs) were harvested at various times thereafter. Alterations in the proportion of leukocyte subsets including CD4(+) T cells, CD8(+) T cells, Treg cells, B cells, NK cells, NK1.1(+) T cells, macrophages and granulocytes were analyzed by FACS. The lungs, liver, pancreas, stomach, jejunum, duodenum, ileum, colon and kidney were harvested and studied by H&E staining. Expression of inflammatory mediators in plasma and tissue were investigated by ELISA. HBI significantly decreased the leukocyte pool though the various leukocyte subsets had different sensitivities to HBI. The administration of PC61 significantly decreased the proportion of Treg cells in spleen, iLN, mLN and blood (reduction of approximately 60%). Irradiation significantly increased the proportion of Treg cells in the spleen, iLN and mLN. HBI induced a systemic inflammatory reaction as demonstrated by increased plasma levels of IL-6, KC/CXCL1 and circulating granulocytes in the blood. Neutrophils also infiltrated the small bowel. The same general patterns were observed whether or not Treg cells were partially depleted with PC61 prior to HBI. These data demonstrate that partial depletion of Treg cells in these mice does not influence HBI-induced inflammatory response and tissue injury, and that combining anti-CD25 therapy with radiation may be safe and well tolerated in a clinical setting.

Show MeSH
Related in: MedlinePlus