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P L Mottram

Publications and source records attributed to P L Mottram.

At least 37 records · Page 2Linked to original sources
PubMed1993

Immunosuppressive antibody treatment prolongs graft survival in two murine models of segmental pancreas transplantation.

Successful pancreas transplantation requires the suppression of both allograft rejection and recurrence of autoimmune disease. In order to study treatments to suppress these two responses, separate models were developed for pancreas allograft rejection and autoimmune disease. In the first model, the diabetic state was induced with streptozotocin in CBA mice prior to the transplantation of pancreas grafts from BALB/c donors. In the absence of autoimmune disease, control mice rejected their grafts in 26 days (median). Antibody treatments (anti-lymphocyte serum and anti-CD4) significantly prolonged allograft survival beyond this time, but not to the extent we have previously reported in the heart graft model. NOD/Lt mice spontaneously developed autoimmune diabetes, and recurrence of disease was seen in isografts at 9.5 days (median). Antibody treatments significantly delayed disease recurrence, with anti-CD4 being the most effective. Heart allografts (CBA donors) in NOD/Lt recipients were rejected within 17 days (median), and the anti-CD4 treatment had a moderate effect in delaying graft survival (median 28 days). Anti-lymphocyte serum did not prolong graft survival. Thus antibody treatment was effective in delaying both rejection and the recurrence of autoimmune disease in segmental pancreas grafts. However, the same doses were not effective in delaying heart rejection in the NOD/Lt model, so it would appear that treatments which inhibit autoimmune disease may not prevent allograft rejection.

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PubMed1993

Evidence that an anthracycline-anti-CD8 immunoconjugate, idarubicin-anti-Ly-2.1, prolongs heart allograft survival in mice.

To examine the potential use of immunoconjugates of drugs and antibodies as immunosuppressive agents, mice were treated with a short course (4 days) of T-cell-specific anti-Ly-2.1 monoclonal antibody, or MAB conjugated to an anthracycline, idarubicin (IDA). The anti-Ly-2.1 MAB had no significant effect on the survival of BALB/c (Ly-2.2) heart allografts in CBA (Ly-2.1) mice, but was a potent immunosuppressive agent when coupled to IDA, with most grafts surviving for > 100 days following treatment with doses ranging from 10 to 120 micrograms IDA, covalently coupled to 1-8 mg MAB. IDA-MAB treated mice with long-surviving heart grafts showed donor-specific tolerance. They did not reject donor-type skin grafts (these survived for > 50 days), but rejected third-party skin in 10-14 days. Heart allografts in these mice survived for > 100 days. Allografts placed 30 days after treatment were rejected, showing a recovery of peripheral T cell function at this time. Newly derived thymic T cells were, however, not required for this recovery since adult thymectomized, IDA-MAB treated animals also recovered T cell function and rejected heart allografts. FACScan analysis of T cells from mice treated with 80 micrograms IDA-4 mg MAB, which had received a heart allograft, showed 95% T cell depletion in the spleen compared with ungrafted, IDA-MAB treated animals, and untreated controls with or without allografts. Splenic T cell depletion was however not significant in CBA mice immunosuppressed with the lower dose of 10 micrograms IDA-MAB. Thus rapid depletion of splenic T cells was not required for immunosuppression induced by IDA-MAB conjugates. However, the minor subpopulation of Ly-2+, which was activated by alloantigen while carrying IDA-MAB, may be depleted during the T cell response to the allograft, resulting in a state of alloantigen-specific tolerance in mice with long-surviving heart allografts.

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PubMed1993

A microsurgical technique for renal transplantation in mice.

A modified technique for the transplantation of primarily vascularized mouse kidneys is described in which the donor was prepared by exposure of the left kidney, dissection of the suprarenal aorta and vena cava and of the ureter and bladder. The recipient was prepared by exposure of the infrarenal aorta and vena cava and isolation of approximately 1 cm of these vessels by proximal and distal 4/0 silk ties. The donor kidney was then perfused and removed to the recipient with the ureter and bladder. The transplant was completed by microsurgical end-to-side anastomosis of the aorta to aorta and vena cava to vena cava and the donor ureter was attached to the recipient bladder via a bladder patch. This technique differed significantly from the previously published technique in using cuffs of donor suprarenal aorta and vena cava rather than dissecting the base of the renal vessels. These changes made the operation easier and reduced ischaemia time from 35-40 to 25-30 min, a substantial improvement which increased both organ and recipient survival.

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PubMed1990

T suppressor cells induced by transfusions and cyclosporine. Studies in the murine cardiac allograft model.

Pregraft transfusion combined with immunosuppression at the time of grafting improves the survival of clinical and experimental allografts. The mechanisms responsible for this effect were investigated in the murine model of cardiac transplantation, combining transfusions 7 to 30 days prior to transplantation with cyclosporine 100 mg/kg, 7 to 20 days pregraft or on days 0, 4, and 6 after grafting. Pregraft DST, third-party blood, and CsA all improved graft survival in the BALB/c-to-CBA donor-recipient combination. In animals treated with DST at 14 days pregrafting, 4/9 grafts survived for greater than 100 days. In those given C57BL/6 blood, or CsA on days 0, 4, 6 postgraft, 1/9 grafts survived for greater than 100 days. When 10(7) spleen cells from DST-treated CBA mice with long-surviving BALB/c heart grafts were transferred to naive CBA mice that then received a BALB/c heart 24 hr later, the transferred cells prolonged graft survival, with all grafts functioning at greater than 40 days, and 4/7 at greater than 100 days. Selective removal of T cells from the spleen cell population prior to transfer showed that L3T4+ T cells, but not Ly-2+ T cells, were required to maintain BALB/c allografts. Combining a short course of CsA with DST was more effective than either treatment alone. The most effective combined treatment was DST at day -14 with 100 mg/kg CsA given on days 0, 4, and 6 postgrafting (8/10 grafts survived greater than 100 days). This treatment also induced splenic suppressor T cells of the L3T4+ Ly-2- phenotype. These results clearly show that L3T4+ splenic T suppressor cells are induced by donor-specific blood transfusion with or without CsA treatment, and that these cells play a role in maintaining long-term tolerance to allografts in the mouse heart transplant model.

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PubMed1989

Cyclosporine increases endothelin-1 binding site density in cardiac cell membranes.

When used in high concentrations, the immunosuppressive agent cyclosporine A has toxic side effects, including cardiac fibrosis and calcification. Cyclosporine-treated mice were used to investigate whether a cyclosporine dose regime which produces cardiac fibrosis and calcification alters the density of the specific binding sites for the endothelial-derived vasoconstrictor polypeptide, endothelin-1. After twenty-one days of treatment the endothelin-1 binding site density in cardiac cell membranes was increased, without any change in selectivity. This increase in endothelin-1 binding site density could contribute to the cytotoxic effects of cyclosporine.

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