Obstetrics and Gynaecology - Research Publications
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ItemLIMITATIONS OF THE CLONAL AGAR ASSAY FOR THE ASSESSMENT OF PRIMARY HUMAN OVARIAN TUMOR-BIOPSIES(CHURCHILL LIVINGSTONE, 1982-01-01)114 biopsy specimens from 70 patients with ovarian carcinoma at all stages of disease were submitted for assessment of clonogenic capacity in agar. A highly significant correlation was found between agar clonogenicity and patient survival after biopsy. However, problems related to inherent tumour heterogeneity, quality of sample and tissue disaggregation indicate that this technique may have limited applicability in the routine assessment of patients. Only 41 biopsy specimens (36%) from 31 patients (44.3%) complied with the prerequisite criteria for agar clonogenic assessment, namely: (a) the confirmed presence of malignant cells in the biopsy, (b) the ability to prepare a single-cell suspension, and (c) adequate viable cell numbers for assay. Furthermore, although the dominant patterns of agar clonogenic growth could be identified and correlated with stage of disease, the heterogeneity in both initial clonogenic capacity and "self-renewal" capacity assessed by the ability of primary clones to propagate in liquid culture and reclone in agar was too inconsistent for the assay to be used as a prognostic index for the individual patient.
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ItemAUTOIMMUNITY CAUSED BY IGNORANT CD8(+) T-CELLS IS TRANSIENT AND DEPENDS ON AVIDITY(AMER ASSOC IMMUNOLOGISTS, 1995-09-01)RIP-Kb mice, which express H-2Kb (Kb) molecules on their pancreatic beta cells, were used to examine the requirements for induction of autoimmune diabetes caused by CD8+ T cells. Previous studies showed that when these mice were crossed to mice expressing a Kb-specific TCR transgene, those CD8+ cells expressing the highest density of the transgenic TCR (presumably the highest avidity cells) were deleted intrathymically due to aberrant expression of Kb at this site. The remaining low avidity cells ignored Kb-bearing beta cells, even after priming, but were able to cause autoimmune diabetes when supplied with Il-2. To examine the properties of high avidity autoreactive CD8+ T cells, the thymic compartment of RIP-Kb mice was replaced with normal tissue to enable the maturation of CD8+ cells expressing the highest density of the transgenic TCR. These high avidity cells generally ignored Kb-expressing beta cells, but became autoaggressive after priming. Importantly, analysis of islet infiltration by CD8+ T cells revealed the presence of infiltrating cells in all mice examined within 3 wk of priming, but such infiltration was not usually apparent at later time points. In some cases, multiple primings were necessary for full development of autoimmunity. This implied that beta cells could act as transient targets for CD8+ T cell attack but could not sustain the stimulation of primed CD8+ cells. These studies indicate that the duration of priming stimulus and the avidity of the autoreactive CD8+ cells profoundly influence the severity of autoimmune disease.
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ItemT-CELL DYSFUNCTION IN THE DIABETES-PRONE BB RAT - A ROLE FOR THYMIC MIGRANTS THAT ARE NOT T-CELL PRECURSORS(ROCKEFELLER UNIV PRESS, 1988-01-01)Diabetes-prone BB (BB-DP) rats express several T cell dysfunctions which include poor proliferative and cytotoxic responses to alloantigen. The goal of this study was to determine the origin of these T cell dysfunctions. When BB-DP rats were thymectomized, T cell depleted, and transplanted with neonatal thymus tissue from diabetes-resistant and otherwise normal DA/BB F1 rats, the early restoration of T cell function proceeded normally on a cell-for-cell basis; i.e., peripheral T cells functioned like those from the thymus donor. Because the thymus in these experiments was subjected to gamma irradiation before transplantation and there was no evidence of F1 chimerism in the transplanted BB-DP rats, it appeared that the BB-DP T cell precursors could mature into normally functioning T cells if the maturation process occurred in a normal thymus. If the F1 thymus tissue was treated with dGua before transplantation, the T cells of these animals functioned poorly like those from untreated BB-DP rats. dGua poisons bone marrow-derived cells, including gamma radiation-resistant cells of the macrophage/dendritic cell lineages, while sparing the thymic epithelium. Therefore, the reversal of the T cell dysfunction depends on the presence in the F1 thymus of gamma radiation-resistant, dGua-sensitive F1 cells. Conversely, thymectomized and T cell-depleted F1 rats expressed T cell dysfunction when transplanted with gamma-irradiated BB thymus grafts. T cell responses were normal in animals transplanted with dGua-treated BB thymus grafts. With increasing time after thymus transplantation, T cells from all animals gradually expressed the functional phenotype of the bone marrow donor. Taken together these results suggest that BB-DP bone marrow-derived cells that are not T cell precursors influence the maturation environment in the thymus of otherwise normal BB-DP T cell precursors.