T cell receptor specificity and diabetes in nonobese diabetic mice.
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Animals↗
Biomedical subjects
A Bendelac
Publications and source records attributed to A Bendelac.
Evidence for a preferential V beta usage by the T cells which adoptively transfer diabetes in NOD mice.
Non-obese diabetic (NOD) mice become spontaneously diabetic as a result of a genetically programmed autoimmune process mediated by autoreactive T lymphocytes and directed against beta cell antigen(s). Studies dealing with T cell receptor (TcR) variable (V) gene usage by such autoreactive T lymphocytes have given contrasted results. Various reasons may explain these discrepancies: the multiplicity of antigenic epitopes putatively recognized by T cells, the ambiguity between specifically committed T cells and passenger lymphocytes homing randomly to the pancreas, the necessarily limited size of the T cell clone panels which have been analyzed for TcR rearrangements and, last but not least, the flexibility of T cell repertoires. To circumvent some of these difficulties, we have decided to concentrate upon the T cell population present in diseased animals and capable of transferring diabetes into young naive NOD recipients. This population, composed of CD4+ and CD8+ T cells, is presumably committed against the relevant beta cell antigens and is the most likely to reveal a bias in V gene usage if such a bias does indeed exist. To find out whether certain V beta genes are more frequently used than others by such pathogenic T cells, T lymphocytes from diabetic donors have been depleted in vitro of defined V beta subsets before being reinoculated into permissive recipients. Out of four V beta families probed under such conditions, three (V beta 8, V beta 5 and V beta 11) are neutral. Their absence neither increases nor reduces the final incidence of successful transfers, indicating that these gene segments are not preferentially used. In contrast, the depletion of V beta 6-positive T cells results in a severe reduction of transfers, suggesting that V beta 6 gene is used with a relatively high frequency by diabetogenic CD4+ and/or CD8+ T cells. To define more precisely which subset uses V beta 6 gene preferentially, we have performed mixing experiments with deleted and intact subsets. The results, based on disease transfer and insulitis severity, indicate that the V beta 6 bias affects predominantly the CD4+ subset. Thus, at variance with several studies concluding that V gene usage in NOD mice is heterogeneous, our present data suggest that disease transferring T cells use a relatively restricted set of V beta genes.
Animals↗
Activation events during thymic selection.
During their differentiation in the mouse thymus, CD4+8- cells undergo several of the sequential changes observed upon normal activation of mature, peripheral CD4+ lymphocytes. Expression of CD69, an early activation marker, is first observed on a minority of cells at the T cell receptor (TCR)lo/med double-positive stage, is maximal (50-90%) on heat-stable antigen (HSA)hi TCRhi double-positive, HSAhi TCRmed CD4+8lo, and HSAhi TCRhi CD4+8- cells, and is downmodulated at the mature HSAlo CD4+8- stage. In contrast, CD44, a late activation marker, is selectively expressed at the HSAlo stage. The set of lymphokines that CD4+8- thymocytes can produce upon stimulation also characteristically expands from mainly interleukin 2 (IL-2) at the HSAhi stage, to IL-2 and very large amounts of IL-4, IL-5, IL-10, and interferon gamma (IFN-gamma) at the HSAlo stage. 1 in 30 HSAlo CD4+8- adult thymocytes secrete IL-4 upon stimulation through their TCR. This frequency is 25% of the frequency of IL-2 producers, about 100-fold above that of peripheral (mainly resting) CD4+ T cells. With time after their generation in organ culture, CD4+8- thymocytes lose their capacity to secrete IL-4, IL-5, and IFN-gamma, but not IL-2. Similarly, the frequency of IL-4, but not of IL-2, producers progressively decreases after emigration to the periphery as judged by direct comparison between thymic and splenic CD4+ cells in newborns, or by following the fate of intrathymically labeled CD4+8- cells in adults after their migration to the spleen. This sequence suggests that thymic selection results from an activation process rather than a simple rescue from death at the double-positive stage, and shows that the functional changes induced after intrathymic activation, although transient, are still evident after export to the periphery.
Animals↗
Intrathymic activation events and the generation of IL-4 producer CD4+8- thymocytes.
The generation of mouse CD4+8- thymocytes appears to involve an activation process. CD69, an early activation marker, is first expressed on 3% of TCRlo/med double-positive thymocytes and peaks (70-90%) at the HSAhi TCRmed CD4+8lo and the HSAhi TCRhi CD4+8- stages, before being downmodulated. CD44, a marker of a later stage of activation is selectively expressed at the HSAlo CD4+8- stage. Functional changes associated with the late activated state, such as the transient acquisition of the potential to secrete IL-4 upon stimulation, are also induced at the HSAlo CD4+8- stage and are still evident after export to the periphery. During thymic selection, interactions of different affinities between TCR/CD4 and self ligand/MHC class II, are likely to induce different degrees of activation. This may impart different functional capabilities--such as the potential to secrete IL-4--to a subset of emerging CD4+ T lymphocytes that express TCRs with intermediate affinities for self. Such a pathway may be involved in the maintenance of tolerance and the prevention of some deleterious autoimmune reactions.
Animals↗
CD4+ and CD8+ T cells acquire specific lymphokine secretion potentials during thymic maturation.
Peripheral CD4+ and CD8+ T lymphocytes carry out different functions during immune reactions, partly as a result of the distinct patterns of lymphokines that they secrete upon stimulation. Using thymic cells from adult and newborn mice as well as from fetal organ cultures, we show here that this functional differentiation occurs inside the thymus and is completed during the single positive stage by the time the T-cell receptor becomes fully coupled to the intracellular activation pathways leading to lymphokine secretion. Surprisingly, CD4+8- thymocytes differ from their immediate progeny, naive peripheral CD4+ cells, in that they secrete a broader range of lymphokines, including interleukins 4, 5 and 10 and gamma-interferon, and more closely resemble immunologically experienced (activated or memory) CD4+ lymphocytes.
Animals↗
CD8+ T cell homing to the pancreas in the nonobese diabetic mouse is CD4+ T cell-dependent.
The adoptive transfer of type I diabetes in nonobese diabetic mice requires the contribution of both CD4+ and CD8+ T cells. To further elucidate the cellular pathway(s) of beta-cell destruction and the responsibility of each subset, high doses of committed T cells from diabetic mice purified to single subsets, were injected into syngeneic nonobese diabetic neonates. The recipients of single or mixed subsets were followed for clinical manifestations of diabetes and examined at 30 days of age for in situ lesions. None of the animals injected with either CD4+ or CD8+ T cells became overtly diabetic during the 30 days of observation whereas 8 of 23 mice inoculated with a mixture of the two subsets developed glycosuria and hyperglycemia. However, insulitis was found in 6 of the 13 mice injected with CD4+ T cells whereas only 1 of the 9 mice injected with CD8+ T cells showed marginal infiltration of the pancreas. The lesions initiated by CD4+ T cells alone were considerably less severe than those induced by the mixture of both subsets, corroborating the fact that overt disease did not occur in the former group. Together, these results suggest a distinct function for each diabetogenic T cell subset. CD4+ T cells, which have the capacity to home to the pancreas, promote in turn the influx of CD8+ effector T cells that do not by themselves accumulate in this organ. These results illustrate a novel form of T-T cell interactions leading to organ specific autoimmune lesions.
Animals↗
Th0 cells in the thymus: the question of T-helper lineages.
Although peripheral naive cells only secrete IL-2 upon primary stimulation, their presumptive immediate precursors, HSAlow CD4+8- thymocytes, can produce a large amount of the set of lymphokines usually associated with preactivated or memory CD4+ lymphocytes: IL-4, IL-5, IL-10 and gamma-IFN. This phenotype can be attributed to true virgin thymocytes and not only to recirculating lymphocytes, because it is found in newborn thymuses and in fetal thymic organ culture. This mature stage of CD4+8- thymocytes is itself preceded by an immature stage (HSAhigh) where only IL-2 and small amounts of gamma-IFN can be elicited by the combination of calcium ionophore and phorbol ester, but not by TCR cross-linking. CD8+4- thymocytes pass through a similar immature HSAhigh stage, where their pattern of lymphokine secretion is not yet differentiated from that of CD4+8- HSA high thymocytes. The subsets acquire their specific profiles at the HSAlow stage. We propose that recent thymic CD4+8- emigrant cells include a significant proportion of Th0 type cells, and that their role is critical to prime the immune system for IL-4 production, as well as to explain the longstanding observations of synergy between helper cell subpopulations in the periphery.
Animals↗
Detection of Epstein-Barr virus in epidermal skin lesions of an immunocompromised patient.
Using in-situ hybridizaiton, we showed the presence of the Epstein-Barr (EB) virus genome in epidermal cells from a patient with chronic lymphocytic leukemia and unusual cutaneous lesions characterized clinically by a maculopapular eruption and histologically by epidermal cell degeneration and lymphoid cell infiltration. Such histologic changes are similar to those seen in graft-versus-host disease. The EB virus genome was mainly detected in the basal, germinative cells of the abnormal epithelium. Specimens of our patient's healthy skin were negative. The presence of EB virus DNA in skin lesions was confirmed by polymerase chain reaction adapted for analysis of paraffin-embedded tissue. These findings indicate that EB virus can infect the human epidermis and that the viral infection may produce a distinctive cutaneous disease.
Aged↗
The nonobese diabetic mouse model. Independent expression of humoral and cell-mediated autoimmune features.
Nonobese diabetic (NOD) mice present concomitant signs of cell-mediated and humoral autoimmunity. Whereas the involvement of the cell-mediated manifestations in the pathogenesis of diabetes has been clearly demonstrated, the origin and the relevance of the humoral manifestations is still unclear. In the present study, we have tried to determine whether the humoral manifestations observed in NOD mice were secondary to the cell-mediated antiislet reaction, or whether they resulted from an autonomous polyclonal activation of B cells, a possibility suggested by the notorious presence of antilymphocyte antibodies with thymocytotoxic properties, in the serum of old NOD females. To discriminate between the two alternatives, we have followed the titers of thymocytotoxic autoantibodies in aging males and females, as well as in F1 hybrids where the organ-specific disease is recessive, and in back-crossed mice where the susceptibility genes responsible for insulitis and diabetes have segregated. In addition to thymocytotoxic antibodies, we have also screened the sera of these animals for hyperglobulinemia, antiinsulin, and anti-DNA autoantibodies that are classically associated with polyclonal B cell activation in autoimmune strains of mice. The results indicate that these humoral anomalies are clearly disconnected from the occurrence of diabetes and even of insulitis. Lymphocytotoxic antibodies appear several weeks after the onset of insulitis in NOD mice, are not correlated with disease occurrence and have no predictive value for its onset. The humoral manifestations that include, beside thymocytotoxic antibodies, antiinsulin antibodies, hyperglobulinemia, but no anti-DNA antibodies, are found at the same frequency in F1 mice as in parental mice in spite of the fact that the former are practically free of insulitis lesions. These anomalies are also randomly distributed among back-crossed mice independently of the presence and the severity of the organ-specific lesions. Altogether, these results suggest that NOD mice, like other autoimmune strains, suffer from a genetically inherited defect of B cell regulation resulting in the hyperproduction of natural autoantibodies.
Age Factors↗
Neonatal induction of allogeneic tolerance prevents T cell-mediated autoimmunity in NOD mice.
Diabetes in the NOD mouse strain is a genetically programmed T cell-mediated autoimmune process that is directed against an as yet unknown antigen target(s) on pancreatic beta cells. To investigate whether the course of the autoimmune disease could be altered by immune manipulations of the T cell repertoire, we have induced allogeneic tolerance by injecting F1 semiallogeneic spleen cells into NOD neonates. This procedure resulted in a significant protection against both insulitis and diabetes. However, although it requires the induction of tolerance, as shown by the failure of non-tolerizing irradiated cells to prevent autoimmunity, protection appeared to be independent of the major histocompatibility complex haplotypes of the F1 spleen cells injected at birth, e.g. (C57BL/6 x NOD)F1, (CBA/Ca x NOD)F1 or (BALB/c x NOD)F1 cells. In addition, a similar degree of protection was induced, whether the tolerant state, as assessed by mixed lymphocyte reaction studies in vitro, was of short duration, approximately 6 weeks, or lasted for more than 12 weeks. Putative veto or suppressor functions of chimeric T cells were ruled out, since mice tolerized with T cell-depleted F1 spleen cells were equally protected. We conclude that the expression of spontaneous T cell-mediated autoimmunity can be modulated by immune manipulations at birth. Whether the protection observed in the present experiments resulted from the production of one or several specific holes in the autoimmune T cell repertoire, i.e. cross-tolerance, or whether it resulted from nonspecific disturbances of the emerging T cell repertoire remains to be elucidated.
Age Factors↗
Acceleration of the onset of diabetes in NOD mice by thymectomy at weaning.
The effect of thymectomy performed at weaning (3 weeks) and at 6-7 weeks of age on the incidence of diabetes was examined in the non-Obese diabetic (NOD) mouse, a spontaneous model of immunologically mediated insulin-dependent diabetes similar to human type I diabetes. When performed at weaning, thymectomy led to a dramatic increase in the incidence of diabetes in NOD females in comparison to sham-thymectomized animals. Conversely, no change in the incidence of the disease or the expression of insulitis was noted when thymectomy was performed in NOD males. When delayed beyond 6-7 weeks of age, thymectomy had no effect on NOD males and females. Flow cytometry analysis of spleen cells from intact mice and mice thymectomized at weaning or at 6-7 weeks of age demonstrated a significant depletion of the T cell subsets in both groups of thymectomized animals. These results indicate that the onset of diabetes in NOD mice is submitted to thymic regulation and that the T cell depletion induced by thymectomy at weaning accelerates the disease, an effect possibly due to the loss of some T cell-dependent suppressor mechanisms.
Age Factors↗
Syngeneic T cell transfer of diabetes into NOD newborn mice: in situ studies of the autoimmune steps leading to insulin-producing cell destruction.
To overcome the limitations of in situ studies during the chronic spontaneous autoimmune process leading to insulin cell destruction and diabetes in non-obese diabetic (NOD) mice, we have developed a model of acute transfer of diabetes into healthy syngeneic newborns. The injection of 20 x 10(6) T cells from adult diabetic mice produced synchronous insulitis within 3 weeks and diabetes within 4-5 weeks in young recipients, at a time when non-injected control mice do not even exhibit histological changes in their pancreases. Sequential studies of pancreases from T cell-transferred mice showed that lymphoid infiltration was preceded by a strong tissue expression of Ia antigen which was restricted to the vessel-associated cells limiting the islet of Langerhans, and which might play a role in the recruitment of circulating T cells inside the islets. Acute destruction of most of the insulin-producing cells, leading to diabetes, could take place within a few days after insulitis had begun. A majority of the inflammatory cells were T lymphocytes, approximately 30% of which expressed interleukin 2 receptors. L3T4+ T cells largely predominated at the early phase of islet invasion whereas the proportion of Ly-2+ T cells substantially increased later when beta cell destruction occurred. In contrast, only a minority of B cells and macrophages participated to the inflammatory process. These data are in keeping with previous demonstrations that both T cell subsets contribute to the autoimmune disease. Furthermore, they suggest that beta cell injury is mediated through a cytotoxic process, which requires the sequential involvement of L3T4+ (helper) and Ly-2+ (cytotoxic) T cells.
Animals↗
Adoptive T cell transfer of autoimmune nonobese diabetic mouse diabetes does not require recruitment of host B lymphocytes.
The autoimmune nonobese diabetic mouse, a model of human juvenile type I diabetes mellitus, exhibits features of both B and T cell autoreactivity against insulin-producing cells. Using the neonatal cell transfer model of the disease, which we have described previously, we have shown that B cell suppression of newborn recipients by anti-mu treatment did not affect the transfer of diabetes by means of T cells. B cell-depleted, purified T cells from diabetic adults were injected into newborns treated with either IR-52, a control rat myeloma protein, or LOMM.9, a rat anti-mouse mu-chain mAb. Both groups developed diabetes over a similar time scale. Although the pancreases in both groups showed massive infiltration by T lymphocytes, B lymphocytes, presumably recruited in the host, were present in the IR-52-treated group, whereas they were absent in the LOMM.9-treated group. Anti-mu-treated diabetic animals showed substantial B cell suppression in vivo and in vitro when compared with IR-52-treated controls. These results suggest that B cell autoreactivity is a secondary phenomenon that is unimportant during the effector phase of diabetes in nonobese diabetic mice.
Animals↗
Prevention of diabetes in nonobese diabetic mice by anti-I-A monoclonal antibodies: transfer of protection by splenic T cells.
The nonobese diabetic (NOD) mouse has been developed as a model for insulin-dependent diabetes. One gene required for the development of diabetes is associated with the major histocompatibility complex. This gene possibly could be linked to class II genes, which show a unique pattern in NOD mice. To evaluate the role of the I-A class II antigen expressed in NOD mice, we studied the effect of anti-I-A monoclonal antibodies on disease onset in vivo. Long-term treatment with anti-class II IgG2a antibodies specific for NOD I-A antigen prevented the spontaneous development of diabetes, as opposed to control antibodies shown not to react with NOD I-A antigen. Anti-class II antibodies apparently elicited active immune suppression, requiring a fully immunocompetent host, rather than passive blockade of class II antigen. Treatment with anti-class II antibody effectively prevented the adoptive transfer of diabetes produced by splenocytes from diabetic NOD mice into newborn mice but failed to prevent adoptive transfer into irradiated adult NOD recipients. Direct evidence for the induction of suppressor cells was obtained from the passive transfer of spleen cells from anti-class II antibody-treated NOD donors. The injection of anti-class II antibody-treated spleen cells collected from NOD donors prevented the development of diabetes, which normally follows transfer of diabetogenic spleen cells into irradiated 8-week-old male NOD recipients. Depletion experiments indicate that CD4+ cells are responsible for anti-class II-induced protection transferred by spleen cells.
Animals↗
[Erythrokeratoderma variabilis (Mendes Da Costa). Ultrastructural study].
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Child, Preschool↗
Syngeneic transfer of autoimmune diabetes from diabetic NOD mice to healthy neonates. Requirement for both L3T4+ and Lyt-2+ T cells.
We have developed a model of syngeneic adoptive transfer for type I diabetes mellitus of NOD mice. This model consists in injecting spleen cells from diabetic adult mice into newborn NOD recipients. 50% of recipients inoculated with 20 X 10(6) cells develop diabetes within the first 10 wk of life, at a time when none of the control littermates have yet become diabetic. The earliest successful transfers are observed at 3 wk of age, at a time when controls do not even exhibit histological changes in their pancreas. In addition we have shown that: (a) both males and females can be adoptively transferred, despite the fact that males rarely develop spontaneous diabetes in our colony; (b) diabetes transfer is a dose-dependent phenomenon that provides an in vivo assay for comparing the autoimmune potential of spleen cells from mice at various stages of their natural history; (c) the susceptibility of the recipients to the transfer is limited in time and declines after 3 wk; and (d) both L3T4+ and Lyt-2+ T cell subsets are necessary for the successful transfer. The neonatal syngeneic transfer provides an effective model for studies of the cellular events involved at regulatory and effector stages of autoimmune type I diabetes.
Animals↗
Nonneoplastic circulating Sézary-like cells in cutaneous T-cell lymphoma. Ultrastructural, immunologic, and T-cell receptor gene-rearrangement studies.
Approximately 67% of peripheral blood lymphocytes in a case of nonmycosis fungoides-type cutaneous T-cell lymphoma, exhibited Sézary-like changes. Immunotyping showed a helper phenotype with an abnormally faint expression of the T3 membrane antigen, while quantitative electron microscopic study was suggestive of neoplasia. However, T-cell receptor gene study did not show any DNA rearrangement in Ficoll-separated blood lymphocytes, whereas clonal T-cell proliferation was simultaneously evidenced in cutaneous (non-Sézary-like) tumor cells. It is concluded that reactive nonneoplastic Sézary-like cells may be present not only in various benign conditions, as previously known, but also in T-cell lymphomas. This study provides further evidence for the nonspecificity of Sézary-like changes, and stresses the utility of T-cell receptor gene rearrangement study for diagnostic and prognostic procedures during the course of T-cell lymphoproliferative disorders.
DNA, Neoplasm↗
Urinary excretion of 5-S-cysteinyldopa is enhanced by PUVA and is independent of skin type.
Urinary excretion of 5-S-cysteinyldopa (5-S-CD) was followed in 20 patients receiving PUVA therapy. Large increases were observed after PUVA treatment, more predominant in males and unrelated to skin types. Relative increases rather than absolute values paralleled cutaneous reactions.
Adult↗