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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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GI injury.Tissues were fixed, thin sectioned and studied with H&E staining. (A) Neutrophil infiltration in jejunum at 3 day after radiation. 200× magnification. The arrow on the image shows a neutrophil cluster. 200× magnification. (B) Crypt hyperplasia at 7 days after radiation. 100× magnification.
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pone-0056607-g009: GI injury.Tissues were fixed, thin sectioned and studied with H&E staining. (A) Neutrophil infiltration in jejunum at 3 day after radiation. 200× magnification. The arrow on the image shows a neutrophil cluster. 200× magnification. (B) Crypt hyperplasia at 7 days after radiation. 100× magnification.

Mentions: It is well known that radiation causes tissue damage in the gastrointestinal (GI) tract. To determine whether depletion of Treg cells amplified radiation-induced tissue injury, the lungs, liver, pancreas, stomach, jejunum, duodenum, ileum, colon and kidney were subjected to histological analysis. The most significant tissue damage was observed in the small intestine. In accordance with increased levels of IL-1β and KC/CXCL1 in the small intestine, neutrophil infiltration was observed in the lamina propia 3 days following irradiation (neutrophils identified by morphology). A representative image is shown in Figure 9A. The number of neutrophils in the lamina propria also increased significantly following irradiation (Table 1).


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)

GI injury.Tissues were fixed, thin sectioned and studied with H&E staining. (A) Neutrophil infiltration in jejunum at 3 day after radiation. 200× magnification. The arrow on the image shows a neutrophil cluster. 200× magnification. (B) Crypt hyperplasia at 7 days after radiation. 100× magnification.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3569437&req=5

pone-0056607-g009: GI injury.Tissues were fixed, thin sectioned and studied with H&E staining. (A) Neutrophil infiltration in jejunum at 3 day after radiation. 200× magnification. The arrow on the image shows a neutrophil cluster. 200× magnification. (B) Crypt hyperplasia at 7 days after radiation. 100× magnification.
Mentions: It is well known that radiation causes tissue damage in the gastrointestinal (GI) tract. To determine whether depletion of Treg cells amplified radiation-induced tissue injury, the lungs, liver, pancreas, stomach, jejunum, duodenum, ileum, colon and kidney were subjected to histological analysis. The most significant tissue damage was observed in the small intestine. In accordance with increased levels of IL-1β and KC/CXCL1 in the small intestine, neutrophil infiltration was observed in the lamina propia 3 days following irradiation (neutrophils identified by morphology). A representative image is shown in Figure 9A. The number of neutrophils in the lamina propria also increased significantly following irradiation (Table 1).

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