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Role of the thymus in transplantation tolerance in miniature swine. I. Requirement of the thymus for rapid and stable induction of tolerance to class I-mismatched renal allografts.

Yamada K, Gianello PR, Ierino FL, Lorf T, Shimizu A, Meehan S, Colvin RB, Sachs DH - J. Exp. Med. (1997)

Bottom Line: Thymectomized swine developed acute cellular rejection characterized by a T cell (CD25(+)) infiltrate, tubulitis, endothelialitis and glomerulitis, and anti-donor CTL reactivity in vitro.Nonthymectomized and sham thymectomized animals had a mild T cell infiltrate with few CD25(+) cells and no anti-donor CTL response in vitro.These results indicate that the thymus is required for rapid and stable induction of tolerance.

View Article: PubMed Central - PubMed

Affiliation: Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, 02129, USA.

ABSTRACT
The almost uniform failure in transplant patients of tolerance-inducing regimens that have been found to be effective in rodents, has made it necessary to examine large animal models before testing of new approaches clinically. Miniature swine have been shown to share many relevant immunologic parameters with humans, and because of their reproducible genetics, have proved extremely useful in providing such a large animal model. We have previously shown that indefinite systemic tolerance to renal allografts in miniature swine is induced in 100% of cases across a two-haplotype class I plus minor histocompatibility antigen disparity by a 12-d course of Cyclosporine A (CyA), in contrast to irreversible rejection observed uniformly without CyA treatment. In the present study, we have examined the role of the thymus during the induction of tolerance by performing a complete thymectomy 21 d before renal transplantation. This analysis demonstrated a striking difference between thymectomized and nonthymectomized animals. Thymectomized swine developed acute cellular rejection characterized by a T cell (CD25(+)) infiltrate, tubulitis, endothelialitis and glomerulitis, and anti-donor CTL reactivity in vitro. Nonthymectomized and sham thymectomized animals had a mild T cell infiltrate with few CD25(+) cells and no anti-donor CTL response in vitro. These results indicate that the thymus is required for rapid and stable induction of tolerance.

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Phenotype of GIC from typical thymectomized and nonthymectomized animals. Flow cytometric analysis of the CD25 expression  (closed histogram) on GIC on POD 8 prepared from renal biopsies taken  from thymectomized (a) and nonthymectomized (b) animals is represented. The negative control antibody staining is also shown (open histogram). The CD8 versus CD4 dot-plot analysis of the GIC on POD 8 is  shown for a thymectomized (c) and nonthymectomized animal (d). The  analysis of the phenotype shows the large number of CD8 single positive  and CD4/8 double positive GIC in both animals.
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Figure 5: Phenotype of GIC from typical thymectomized and nonthymectomized animals. Flow cytometric analysis of the CD25 expression (closed histogram) on GIC on POD 8 prepared from renal biopsies taken from thymectomized (a) and nonthymectomized (b) animals is represented. The negative control antibody staining is also shown (open histogram). The CD8 versus CD4 dot-plot analysis of the GIC on POD 8 is shown for a thymectomized (c) and nonthymectomized animal (d). The analysis of the phenotype shows the large number of CD8 single positive and CD4/8 double positive GIC in both animals.

Mentions: To assess the number of activated T cells in the graft and PBLs semiquantitatively, GICs and PBLs were examined by flow cytometry with the anti-CD25 mAb. Fig. 5 shows CD25 expression on GICs on POD8 in representative thymectomized and nonthymectomized animals. CD25 was expressed on 36.6% of CD2-positive GICs in the thymectomized animal, whereas only 1.4% of CD2-positive GICs expressed CD25 in the nonthymectomized animal (Fig. 5, a and b). These results were consistent with the immunohistological findings (Fig. 4, c and d). CD25 expression in the GICs of thymectomized animals decreased over time (data not shown). Representative CD8 versus CD4 staining of GICs from a thymectomized animal (Fig. 5 c) and a nonthymectomized animal (Fig. 5 d) demonstrated that the majority of the GICs were CD8 single positive or CD4/8 double positive cells, with very few CD4 single positive cells. Two-color flow cytometric analysis indicated that the CD25-positive cells in the thymectomized animals were observed in both the CD8-positive and CD4-positive cells, which would correspond mainly to the CD8 single positive and CD4/8 double positive cells since the CD4 single positive cell population comprised <2% of the GICs. In addition, for both thymectomized and nonthymectomized animals, most of GICs were likely to be T cells since >80% of GICs were CD2-positive cells (data not shown) and >80% of GICs were also CD4 and/or CD8-positive cells (Fig. 5, c and d). No major differences were observed in the expression of CD25 in the PBLs when comparing thymectomized and nonthymectomized animals (data not shown).


Role of the thymus in transplantation tolerance in miniature swine. I. Requirement of the thymus for rapid and stable induction of tolerance to class I-mismatched renal allografts.

Yamada K, Gianello PR, Ierino FL, Lorf T, Shimizu A, Meehan S, Colvin RB, Sachs DH - J. Exp. Med. (1997)

Phenotype of GIC from typical thymectomized and nonthymectomized animals. Flow cytometric analysis of the CD25 expression  (closed histogram) on GIC on POD 8 prepared from renal biopsies taken  from thymectomized (a) and nonthymectomized (b) animals is represented. The negative control antibody staining is also shown (open histogram). The CD8 versus CD4 dot-plot analysis of the GIC on POD 8 is  shown for a thymectomized (c) and nonthymectomized animal (d). The  analysis of the phenotype shows the large number of CD8 single positive  and CD4/8 double positive GIC in both animals.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2199031&req=5

Figure 5: Phenotype of GIC from typical thymectomized and nonthymectomized animals. Flow cytometric analysis of the CD25 expression (closed histogram) on GIC on POD 8 prepared from renal biopsies taken from thymectomized (a) and nonthymectomized (b) animals is represented. The negative control antibody staining is also shown (open histogram). The CD8 versus CD4 dot-plot analysis of the GIC on POD 8 is shown for a thymectomized (c) and nonthymectomized animal (d). The analysis of the phenotype shows the large number of CD8 single positive and CD4/8 double positive GIC in both animals.
Mentions: To assess the number of activated T cells in the graft and PBLs semiquantitatively, GICs and PBLs were examined by flow cytometry with the anti-CD25 mAb. Fig. 5 shows CD25 expression on GICs on POD8 in representative thymectomized and nonthymectomized animals. CD25 was expressed on 36.6% of CD2-positive GICs in the thymectomized animal, whereas only 1.4% of CD2-positive GICs expressed CD25 in the nonthymectomized animal (Fig. 5, a and b). These results were consistent with the immunohistological findings (Fig. 4, c and d). CD25 expression in the GICs of thymectomized animals decreased over time (data not shown). Representative CD8 versus CD4 staining of GICs from a thymectomized animal (Fig. 5 c) and a nonthymectomized animal (Fig. 5 d) demonstrated that the majority of the GICs were CD8 single positive or CD4/8 double positive cells, with very few CD4 single positive cells. Two-color flow cytometric analysis indicated that the CD25-positive cells in the thymectomized animals were observed in both the CD8-positive and CD4-positive cells, which would correspond mainly to the CD8 single positive and CD4/8 double positive cells since the CD4 single positive cell population comprised <2% of the GICs. In addition, for both thymectomized and nonthymectomized animals, most of GICs were likely to be T cells since >80% of GICs were CD2-positive cells (data not shown) and >80% of GICs were also CD4 and/or CD8-positive cells (Fig. 5, c and d). No major differences were observed in the expression of CD25 in the PBLs when comparing thymectomized and nonthymectomized animals (data not shown).

Bottom Line: Thymectomized swine developed acute cellular rejection characterized by a T cell (CD25(+)) infiltrate, tubulitis, endothelialitis and glomerulitis, and anti-donor CTL reactivity in vitro.Nonthymectomized and sham thymectomized animals had a mild T cell infiltrate with few CD25(+) cells and no anti-donor CTL response in vitro.These results indicate that the thymus is required for rapid and stable induction of tolerance.

View Article: PubMed Central - PubMed

Affiliation: Transplantation Biology Research Center, Massachusetts General Hospital/Harvard Medical School, Boston, Massachusetts, 02129, USA.

ABSTRACT
The almost uniform failure in transplant patients of tolerance-inducing regimens that have been found to be effective in rodents, has made it necessary to examine large animal models before testing of new approaches clinically. Miniature swine have been shown to share many relevant immunologic parameters with humans, and because of their reproducible genetics, have proved extremely useful in providing such a large animal model. We have previously shown that indefinite systemic tolerance to renal allografts in miniature swine is induced in 100% of cases across a two-haplotype class I plus minor histocompatibility antigen disparity by a 12-d course of Cyclosporine A (CyA), in contrast to irreversible rejection observed uniformly without CyA treatment. In the present study, we have examined the role of the thymus during the induction of tolerance by performing a complete thymectomy 21 d before renal transplantation. This analysis demonstrated a striking difference between thymectomized and nonthymectomized animals. Thymectomized swine developed acute cellular rejection characterized by a T cell (CD25(+)) infiltrate, tubulitis, endothelialitis and glomerulitis, and anti-donor CTL reactivity in vitro. Nonthymectomized and sham thymectomized animals had a mild T cell infiltrate with few CD25(+) cells and no anti-donor CTL response in vitro. These results indicate that the thymus is required for rapid and stable induction of tolerance.

Show MeSH
Related in: MedlinePlus