PubMed Health⌕ Search

Biomedical subjects

D Faustman

Publications and source records attributed to D Faustman.

34 records · Page 2Linked to original sources
PubMed1993

Expression of major histocompatibility complex antigens in cultures of clonally derived human myoblasts.

We examined class I and class II HLA antigen expression by flow cytometry in clonal cultures derived from normal human skeletal muscle biopsies. Both HLA class I and class II antigens were constitutively expressed in all clones studied. By altering the constituents of the culture medium, we could modulate the expression of HLA class II but not HLA class I antigens. We noted heterogeneity in the expression of HLA class II antigens among different clones; an increased expression was associated with an increased propensity of myoblasts to fuse. These findings indicate that normal aneurally cultured myoblasts may express both HLA class I and class II antigens, that this expression may be modulated by in vitro agents, and that the presence of these antigens may relate to the process of in vitro myoblast fusion.

Cell Adhesion Molecules, Neuronal↗
PubMed1991

Linkage of faulty major histocompatibility complex class I to autoimmune diabetes.

Pancreatic islet cells are the targets of an autoimmune response in type I diabetes. In the nonobese diabetic (NOD) mouse model of autoimmune diabetes, expression of major histocompatibility complex (MHC) class I proteins was inversely correlated with diabetes; in this mouse a mutation in the MHC class II-linked gene for the putative MHC class I peptide transporter was also present. Mice deficient in MHC class I expression because they do not produce beta 2-microglobulin also developed late onset autoimmune diabetes. In cells from humans with type I diabetes expression of MHC class I was decreased; subsets of prediabetics categorized as most likely to become hyperglycemic also had low MHC class I. T cell responses to self antigens are faulty in diabetics. In sets of genetically identical twins that are discordant for diabetes, the defect appeared to reside with the antigen presenting cell. Thus, a lack of surface MHC class I protein is associated with autoimmune diabetes; the concomitant defect in antigen presentation may impair the development of self tolerance, which could result in autoimmune disease.

Animals↗
PubMed1991

Prevention of xenograft rejection by masking donor HLA class I antigens.

Destruction of target cells by cytotoxic T lymphocytes requires the presence of HLA (human lymphocyte antigen) class I antigens on the target cells for adhesion as well as for triggering of the antigen-specific T cell receptor. Rejection of xenogeneic human pancreatic islets and liver was circumvented by masking, before transplantation, donor antigens with F(ab')2 antibody fragments to HLA class I or tissue-specific epitopes. This strategy eliminated the need for recipient immunosuppression and allowed islet xenograft survival beyond 200 days, as demonstrated functionally by C peptide secretion as well as by histology. These in vivo observations are consistent with the importance of donor HLA class I in eliciting graft rejection and have potential applicability to the successful transplantation of other HLA class I-bearing donor tissues.

Animals↗
PubMed1991

T-lymphocyte changes linked to autoantibodies. Association of insulin autoantibodies with CD4+CD45R+ lymphocyte subpopulation in prediabetic subjects.

The onset of insulin-dependent (type I) diabetes is predictable before hyperglycemia by the presence of islet cell autoantibodies (ICAs) and competitive insulin autoantibodies (CIAAs). CIAA+ICA+ first-degree relatives of individuals with type I diabetes have increased numbers of CD4 cells bearing the CD45R antigen and reciprocal depressions of the CD4 cells bearing the CD29 determinant. In addition, depressed CD4/CD8 ratios are present. In this study, we investigated the correlation between autoantibody levels and T-lymphocyte changes in the prediabetic state. The data demonstrate a clear linear relationship between rising CIAA levels, a marker of disease rate, and rising elevations in the CD4+CD45R+/CD4+CD29+ ratio in 37 CIAA+ICA+ and CIAA+ICA- relatives (r = 0.93). In marked contrast, the degree of CD4/CD8 depression found in individuals with prediabetes or long-term diabetes failed to correlate with either CIAA (r = 0.32) or ICA (r = 0.29) levels. The investigation of T-lymphocyte changes in siblings of individuals with type I diabetes with different stable autoantibody patterns (CIAAs and/or ICAs), and thus varying risks for diabetes, revealed differences in the prediabetic groups. Fifteen CIAA+ICA- relatives with high CIAA levels (greater than 80 nU/ml) had high CD4+CD45R+/CD4+CD29+ ratios (P = 0.03) and depressed CD4/CD8 ratios (P = 0.008). In contrast, CIAA+ICA- relatives with low CIAA levels (39-80 nU/ml), and thus low risk of diabetes, had no alteration in their CD4/CD8 ratio (P = 0.75) or CD4+CD45R+/CD4+CD29+ ratio (P = 0.33). Nineteen CIAA-ICA+ siblings with a predicted intermediate risk for diabetes showed heterogeneity in the presence of T-lymphocyte abnormalities.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗
PubMed1990

Analysis of T lymphocyte subsets in all stages of diabetes.

Direct immunofluorescence analysis of circulating blood lymphocytes from patients with all stages of Type I diabetes revealed marked phenotypic abnormalities among all major T-lymphocyte subpopulations. The alterations were most pronounced in the prediabetics and comprised a stimulation of the T4+2H4+ and T8+2H4+ suppressor inducer subpopulations and corresponding depression of the T4+4B4+ helper inducers.

Adolescent↗
PubMed1989

Abnormal T-lymphocyte subsets in type I diabetes.

Type I (insulin-dependent) diabetes mellitus is a slow autoimmune disease associated with the selective destruction of beta-cells in the islets of Langerhans. Recent studies in humans indicate that autoantibodies to insulin and islets of Langerhans appear years before overt diabetes and identify a normoglycemic prediabetic state. To determine whether type I diabetes mellitus represents a generalized immunologic disorder, we studied the phenotypic characteristics of peripheral blood lymphocytes from all stages, i.e., prediabetic, new-onset diabetic, and long-term diabetic patients, with the anti-2H4 monoclonal antibody CD45R, which defines a human suppressor-inducer subset, and the anti-4B4 monoclonal antibody CDw29, which defines a human helper-inducer subset of peripheral blood lymphocytes. All 22 prediabetic patients had elevated T4+2H4+ (suppressor-inducer) cells and reciprocal depressed T4+4B4+ (helper-inducer) cells compared with healthy age-matched control subjects. In addition, the T4/T8 ratio in prediabetic patients was decreased compared with the age-matched control subjects. The abnormal T4+2H4+ and T4+4B4+ subsets were resolved in 20 new-onset and 15 long-term diabetic patients. Family studies showed that the changes in the 2H4 and 4B4 antigens were not part of an inherited polymorphic determinant, because these markers were normal in unaffected siblings and parents. Ten prediabetic patients were restudied greater than 1 yr after the original analysis and showed the persistence of the observed changes. This abnormal increase in suppressor-inducer cells and decrease in helper-inducer cells among islet and insulin antibody-positive prediabetic patients may be of help in understanding diabetes pathogenesis and may also be an early noninvasive screening tool for the detection of the prediabetic state.

Adolescent↗
PubMed1984

Lymphocyte transfusions prevent diabetes in the Bio-Breeding/Worcester rat.

The Bio-Breeding/Worcester (BB/W) rat develops spontaneous autoimmune diabetes similar to human insulin-dependent diabetes mellitus. Transfusions of whole blood from the nondiabetic W-line of BB/W rats prevent the syndrome in diabetes-prone recipients. We report three experiments designed to determine which blood component is protective. In all experiments, diabetes-prone BB/W rats 23 to 35 d of age were given four or six weekly intravenous injections. In the first experiment, animals received either saline or transfusions of erythrocytes, white blood cells, or plasma from W-line donors. Diabetes occurred in 7/22 (32%) erythrocyte, 2/27 (7%) white cell, 14/24 (58%) plasma, and 15/27 (56%) saline recipients (P less than 0.001). At 120 d of age, peripheral blood was obtained from nondiabetic rats. Fluorescence-activated cell sorter analysis of OX 19 tagged leucocytes revealed 35% T lymphocytes in white cell recipients (n = 13), compared with 9% in saline recipients (n = 7; P less than 0.001). Responsiveness to concanavalin A was also increased in the white cell group, whereas the frequency of both insulitis and thyroiditis was decreased. In the second experiment, 1/19 (5%) rats transfused with W-line spleen cells developed diabetes, as contrasted with 12/18 (67%) recipients of diabetes-prone spleen cells and 19/31 (61%) noninjected controls (P less than 0.001). In the third experiment, diabetes-prone rats received either W-line blood treated with a cytotoxic anti-T lymphocyte antibody plus complement, untreated blood, or saline. Diabetes occurred in 8/20 (40%), 1/20 (5%), and 13/19 (68%) rats in each group, respectively (P less than 0.001). We conclude that transfusions of W-line T lymphocytes prevent diabetes in the BB/W rat.

Animals↗
PubMed1982

Demonstration of active tolerance in maintenance of established islet of Langerhans allografts.

Streptozotocin-induced diabetes in mice can be reversed by transplantation of islets of Langerhans from histoincompatible mice if the islets are treated with anti-Ia-serum and complement before transplantation. Here we show that anti-Ia-treated islets most likely induce tolerance in the recipient animals. Daily injections of recipient-specific anti-I-J-serum (beginning 80 or more days after transplantation) and small numbers of donor splenocytes caused the prompt rejection of the islets in half of the animals; neither anti-I-J-serum nor donor splenocytes alone were effective. It is likely that rejection of established allografts after this treatment is the result of abolition of the activity of allograft-specific suppressor cells.

Animals↗
PubMed1982

Transplantation without immunosuppression.

Exciting new findings have been reported in the past few years that indicate that islets can be transplanted successfully across major histocompatibility barriers without the continuous use of immunosuppressive agents by techniques designed to eliminate passenger leukocytes. In vitro culture of donor islets either at a low temperature (24 degrees C) with a single injection of antilymphocyte serum or culture of megaislets in the presence of 95% O2 before transplantation permitted the successful transplantation of islet allografts and xenografts (rat to mouse). Definitive evidence in support of the passenger leukocyte concept has been obtained recently. Mouse islet cells have been shown to express the class I antigens of the H-2 complex, but do not express Ia antigens. Treatment of fresh mouse islets with specific anti-Ia sera and complement completely prevented rejection of islets transplanted across a major histocompatibility barrier. These findings indicate that Ia-positive cells (possibly dendritic cells) are primarily responsible for the initiation of immune rejection of the transplants. This is of particular importance with respect to the eventual transplantation of islets into human diabetics since it may be feasible to utilize antisera to HLA-DR antigens for pretreatment of islets before transplantation. In addition, these new developments may also be applicable to the transplantation of other organs such as the parathyroid, heart, kidney, liver, and skin.

Animals↗
PubMed1981

Prolongation of murine islet allograft survival by pretreatment of islets with antibody directed to Ia determinants.

Islets of Langerhans treated with donor-specific anti-Ia serum and complement were transplanted across a major histocompatibility barrier into nonimmunosuppressed diabetic mice. The allografts survived in all recipients for at least 200 days after transplantation. Rejection of an established allograft could be induced by intravenous injection of donor splenocytes. This demonstrates that allografts can serve as targets for immune rejection and supports the possible role of Ia-positive passenger lymphoid cells in initiation of immune rejection. The results show that immunosuppression of the recipient is not a prerequisite for successful transplantation.

Animals↗
PubMed1980

Murine pancreatic beta-cells express H-2K and H-2D but not Ia antigens.

Direct microcytotoxicity testing and absorption analyses were employed to determine whether H-2K, H-2D, and Ia antigens are present on murine islet of Langerhans cells. Products of the H-2K and H-2D loci were found on beta-cells from three different mouse strains, but I-region (Ia) antigens were not detected. The absence of Ia gene products from islet cells may be of importance in explaining the survival of islet allografts across major histocompatibility barriers.

Animals↗
PubMedDate not supplied

The role of the proteasome in autoimmunity.

Type 1 diabetes is believed to be caused by T cell-mediated autoimmunity, with a prediabetic state characterized by the production of autoantibodies specific for proteins expressed by pancreatic beta cells. The non-obese diabetic (NOD) mouse is a spontaneous model of Type 1 diabetes with a strong genetic component that maps to the major histocompatibility complex (MHC) region of the genome. A specific proteasome defect has now been identified in NOD mouse lymphocytes that results from down-regulation of expression of the proteasome subunit LMP2, which is encoded by a gene in the MHC genomic region. This defect both prevents the proteolytic processing required for the production and activation of the transcription factor nuclear factor-kappaB (NF-kappaB), which plays an important role in immune and inflammatory responses, in addition to increasing the susceptibility of the affected cells to apoptosis induced by tumor necrosis factor-alpha (TNF-alpha). The proteasome dysfunction is both tissue- and developmental stage-specific and likely contributes to disease pathogenesis and tissue targeting.

Animals↗