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Biomedical subjects

T M Ellis

Publications and source records attributed to T M Ellis.

At least 37 records · Page 2Linked to original sources
PubMed2001

Adeno-associated virus vector-mediated IL-10 gene delivery prevents type 1 diabetes in NOD mice.

The development of spontaneous autoimmune diabetes in nonobese diabetic (NOD) mice provides for their use as a model of human type 1 diabetes. To test the feasibility of muscle-directed gene therapy to prevent type 1 diabetes, we developed recombinant adeno-associated virus (rAAV) vectors containing murine cDNAs for immunomodulatory cytokines IL-4 or IL-10. Skeletal muscle transduction of female NOD mice with IL-10, but not IL-4, completely abrogated diabetes. rAAV-IL-10 transduction attenuated the production of insulin autoantibodies, quantitatively reduced pancreatic insulitis, maintained islet insulin content, and altered splenocyte cytokine responses to mitogenic stimulation. The beneficial effects were host specific, as adoptive transfer of splenocytes from rAAV IL-10-treated animals rapidly imparted diabetes in naive hosts, and the cells contained no protective immunomodulatory capacity, as defined through adoptive cotransfer analyses. These results indicate the utility for rAAV, a vector with advantages for therapeutic gene delivery, to transfer immunoregulatory cytokines capable of preventing type 1 diabetes. In addition, these studies provide foundational support for the concept of using immunoregulatory agents delivered by rAAV to modulate a variety of disorders associated with deleterious immune responses, including allergic reactions, transplantation rejection, immunodeficiencies, and autoimmune disorders.

Adjuvants, Immunologic↗
PubMed2001

Human thymic epithelial cells inhibit IL-15- and IL-2-driven differentiation of NK cells from the early human thymic progenitors.

T/NK progenitors are present in the thymus; however, the thymus predominantly promotes T cell development. In this study, we demonstrated that human thymic epithelial cells (TEC) inhibit NK cell development. Most ex vivo human thymocytes express CD1a, indicating that thymic progenitors are predominantly committed to the T cell lineage. In contrast, the CD1a(-)CD3(-)CD56(+) NK population comprises only 0.2% (n = 7) of thymocytes. However, we observed increases in the percentage (20- to 25-fold) and absolute number (13- to 71-fold) of NK cells when thymocytes were cultured with mixtures of either IL-2, IL-7, and stem cell factor or IL-15, IL-7, and stem cell factor. TEC, when present in the cultures, inhibited the increases in the percentage (3- to 10-fold) and absolute number (3- to 25-fold) of NK cells. Furthermore, we show that TEC-derived soluble factors inhibit generation of NK-CFU and inhibit IL15- or IL2-driven NK cell differentiation from thymic CD34(+) triple-negative thymocytes. The inhibitory activity was found to be associated with a 8,000- to 30,000 Da fraction. Thus, our data demonstrate that TEC inhibit NK cell development from T/NK CD34(+) triple negative progenitors via soluble factor(s), suggesting that the human thymic microenvironment not only actively promotes T cell maturation but also controls the development of non-T lineage cells such as the NK lineage.

Antigens, CD34↗
PubMed2001

Alterations in CD30(+) T cells in monoclonal gammopathy of undetermined significance.

Monoclonal gammopathy of unknown significance (MGUS) is a monoclonal B cell expansion characterized by high levels of circulating monoclonal antibody that affects 3% of individuals over the age of 70. Although this is considered benign, a high percentage of MGUS patients develop a debilitating peripheral autoimmune neuropathy and have a significantly increased risk for progression to multiple myeloma. Here we show that the relative numbers of the CD30(+) T cell subset and levels of CD30 expression are elevated in activated lymphocytes from normal aged individuals (> or =60 years) and in MGUS patients, when compared to younger controls. PBL from MGUS patients and age-matched controls produced comparable levels of IL-6 when activated with anti-CD3 plus IL-2, and costimulation with a soluble form of CD30 ligand (sCD30L/CD8alpha) augmented anti-CD3 inducible IL-6 production similarly in both groups. However, MGUS PBL also produced measurable IL-6 when activated with sCD30L/CD8alpha alone. This capability was associated with the unique presence of CD30(+) T cells in the peripheral blood of MGUS patients. Furthermore, a higher percentage of activated MGUS T cells express CD30 when activated by incubation with idiotype-expressing autologous serum (68 +/- 13) than those activated by anti-CD3 plus IL-2 (43 +/- 7). These results indicate that quantitative alterations in CD30(+) T cells accompany aging and MGUS and that these cells may contribute to the chronic activation of B cells though the production of IL-6.

Aged↗
PubMed2001

Alterations in peripheral B cells and B cell progenitors following androgen ablation in mice.

The production of B lymphocytes is regulated in part by physiologic levels of androgens and estrogens. While these sex hormones down-regulate B lymphopoiesis, augmentation of B lymphopoiesis occurs under conditions where androgen or estrogen levels are decreased. In this study we examine the effect of androgen ablation of male mice on B lymphopoiesis and on the phenotypic composition of peripheral B lymphocyte populations. Spleen and thymic weights are significantly increased following castration, as is the total number of peripheral blood lymphocytes. However, the absolute numbers of B cells in the periphery are selectively increased following castration; the numbers of T cells, NK cells and granulocytes remain unchanged. The increase in circulating B cells is due largely to increases in the numbers of recent bone marrow emigrants expressing a B220(lo+)CD24(hi+) phenotype and these cells remain significantly elevated in castrated mice for up to 54 days post-castration. Similar increases in the percentages of newly emigrated B cells are observed in mice that lack a functional androgen receptor (TFM:). Finally, assessments of B cell progenitors in the bone marrow revealed significant increases in the relative numbers of IL-7-responsive B cell progenitors, including cells in Hardy fractions B (early pro-B cells), C (late pro-B cells), D (pre-B cells) and E (immature B cells). These findings demonstrate that androgen ablation following castration significantly and selectively alters the composition of peripheral B cells in mice. Further, these alterations result from the potentiating effects of androgen ablation on IL-7-responsive pro-B cell progenitors.

Androgens↗
PubMed2000

Characterization of the CD30L binding domain on the human CD30 molecule using anti-CD30 antibodies.

CD30 and its counter-receptor CD30 ligand (CD30L) are members of the TNF-receptor/TNFalpha superfamily and function to regulate lymphocyte survival and differentiation. Several monoclonal antibodies (MAbs) have been developed against CD30 and, based on mutual inhibition assays, are grouped into three nonoverlapping serologic clusters. However, the relationship between the epitopes recognized by the antibodies comprising each cluster and the binding domain for CD30L is not known. Using a soluble CD30L/CD8alpha chimeric protein, we assessed the ability of anti-CD30 MAb to inhibit the binding of CD30L to CD30 expressed by the CD30+ Karpas 299 cell line. CD30L binding by CD30 is blocked by MAb that recognize epitopes belonging to cluster Group A (like Ber-H2, Ber-H8, and HRS-4) as well as cluster Group C (like HeFi-1 and M44). Cluster Group B antibodies, including M67 and Ki-1, do not affect CD30L binding to CD30. The pattern of CD30L binding inhibition shows only limited correspondence to the functional capacity of some anti-CD30 MAb to trigger CD30 signaling. Finally, we demonstrate that the anti-CD30L MAb M81 also completely inhibits CD30/CD30L interaction. This information is useful for applying these MAbs in functional studies to further investigate the CD30/CD30L system and for designing assays for soluble CD30L.

Antibodies, Monoclonal↗
PubMed2000

H9N2 influenza viruses possessing H5N1-like internal genomes continue to circulate in poultry in southeastern China.

The transmission of H9N2 influenza viruses to humans and the realization that the A/Hong Kong/156/97-like (H5N1) (abbreviated HK/156/97) genome complex may be present in H9N2 viruses in southeastern China necessitated a study of the distribution and characterization of H9N2 viruses in poultry in the Hong Kong SAR in 1999. Serological studies indicated that H9N2 influenza viruses had infected a high proportion of chickens and other land-based birds (pigeon, pheasant, quail, guinea fowl, and chukka) from southeastern China. Two lineages of H9N2 influenza viruses present in the live-poultry markets were represented by A/Quail/Hong Kong/G1/97 (Qa/HK/G1/97)-like and A/Duck/Hong Kong/Y280/97 (Dk/HK/Y280/97)-like viruses. Up to 16% of cages of quail in the poultry markets contained Qa/HK/G1/97-like viruses, while about 5% of cages of other land-based birds were infected with Dk/HK/Y280/97-like viruses. No reassortant between the two H9N2 virus lineages was detected despite their cocirculation in the poultry markets. Reassortant viruses represented by A/Chicken/Hong Kong/G9/97 (H9N2) were the major H9N2 influenza viruses circulating in the Hong Kong markets in 1997 but have not been detected since the chicken slaughter in 1997. The Qa/HK/G1/97-like viruses were frequently isolated from quail, while Dk/HK/Y280/97-like viruses were predominately associated with chickens. The Qa/HK/G1/97-like viruses were evolving relatively rapidly, especially in their PB2, HA, NP, and NA genes, suggesting that they are in the process of adapting to a new host. Experimental studies showed that both H9N2 lineages were primarily spread by the aerosol route and that neither quail nor chickens showed evidence of disease. The high prevalence of quail infected with Qa/HK/G1/97-like virus that contains six gene segments genetically highly related to HK/156/97 (H5N1) virus emphasizes the need for surveillance of mammals including humans.

Animals↗
PubMed2000

Acceleration of type 1 diabetes by a coxsackievirus infection requires a preexisting critical mass of autoreactive T-cells in pancreatic islets.

Coxsackievirus infections have been proposed as an environmental trigger for the development of T-cell-mediated autoimmune (type 1) diabetes by either providing a molecular mimic of the candidate pancreatic beta-cell autoantigen GAD or inducing bystander inflammation in the pancreas. In this study in the NOD mouse model, we found that infection with a pancreatrophic coxsackievirus isolate can accelerate type 1 diabetes development through the induction of a bystander activation effect, but only after a critical threshold level of insulitic beta-cell-autoreactive T-cells has accumulated. Thus, coxsackievirus infections do not appear to initiate beta-cell autoreactive immunity but can accelerate the process once it is underway. These findings indicate that the timing of a coxsackievirus infection, rather than its simple presence or absence, may have important etiological implications for the development of T-cell-mediated autoimmune type 1 diabetes in humans.

Animals↗
PubMed1999

Sequence data suggests big liver and spleen disease virus (BLSV) is genetically related to hepatitis E virus.

A monoclonal antibody (mAb) that reacted specifically with a 16 kDa big liver and spleen disease virus (BLSV) protein was used to identify the protein in western immunoblots of infected liver extracts and enable partial amino acid sequence analysis of the protein. Based on this sequence, a degenerate primer was designed that was used in conjunction with random hexamers in a reverse transcriptase-POR (RT PCR), to amplify a 523 bp product from RNA extracted from homogenates of BLSV-infected livers. There was 62% nucleotide sequence identity between this sequence and the sequence of the helicase gene of human hepatitis E virus (HEV). POR primers designed from this 523 bp fragment were able to amplify a 490 bp product from livers of virus-infected chickens but not chickens from virus-free flocks.

Animals↗
PubMed1999

Serological evidence of an Australian bovine lentivirus.

Recombinant 26 kDa capsid (CA) proteins of bovine lentiviruses, bovine immunodeficiency virus (BIV) and Jembrana disease virus (JDV), were expressed in Escherichia coli and utilised as antigens for an enzyme-linked immunosorbent assay (ELISA) and a western immunoblot (WIB) procedure for the detection of antibody in dairy cattle in Western Australia. A total of 690 serum samples, 30 from each of 23 farms, were tested by ELISA with a JDV CA protein antigen, and antibody was detected in 3.8% (p<0.05) of the sera. Nine sera from each farm were also tested by WIB with JDV CA protein antigens and antibody was detected in 15.9% of these samples. All ELISA-positive results were also WIB-positive, and all sera antibody-positive by WIB with JDV CA protein antigens were also antibody-positive by the WIB using recombinant BIV CA antigens. This study showed that recombinant protein antigens can be used for serological tests to detect bovine lentivirus infection in Australia.

Animals↗
PubMed1999

Heterophile antibodies segregate in families and are associated with protection from type 1 diabetes.

Markedly elevated levels of serum IL-4 were reported previously in 50% of a small group of type 1 diabetes nonprogessors. To determine the patterns of expression for this phenotype, a larger cohort of 58 families containing type 1 diabetic patients was examined. Analysis of the two-site ELISA assay used to measure serum IL-4 revealed evidence for heterophile antibodies, i.e., nonanalyte substances in serum capable of binding antibodies mutivalently and providing erroneous analyte (e.g., IL-4) quantification. Interestingly, relatives without type 1 diabetes were significantly more likely to have this phenotype than were patients with the disease (P = 0.003). In addition, the trait appears to have clustered within certain families and was associated with the protective MHC allele DQB1*0602 (P = 0.008). These results suggest that heterophile antibodies represent an in vivo trait associated with self-tolerance and nonprogression to diabetes.

Alleles↗
PubMed1999

Comparative immunogenicity of two bivalent botulinum vaccines.

OBJECTIVE: To compare the ability of a new single-dose botulinum vaccine containing a non-mineral oil adjuvant with a single dose of a conventional botulinum vaccine product to produce antibody to Clostridium botulinum types C and D in cattle in Northern Australia. DESIGN AND PROCEDURE: One hundred and fifty Brahman steer weaners were randomly divided into two groups receiving either a single dose of CSL Bivalent Botulinum vaccine or Websters Singvac. Blood samples were collected at 0, 8 and 24 weeks and tested by antibody ELISA. The final samples were also tested by the toxin neutralisation test, to test titres of neutralising antibody. RESULTS: Six months after inoculation, cattle vaccinated with Websters Singvac had ELISA antibody response twice that of CSL conventional product. However, this difference was only evident for neutralising antibody to type C botulinum toxin. Both products produced similar titres of type D neutralising antibody after a single dose. CONCLUSION: Websters' Singvac produces a greater neutralising antibody response to type C botulism upon single inoculation than a conventional vaccine. The product produces an equivalent neutralising antibody response to type D.

Animals↗
PubMed1999

No alteration in T lymphocyte expression of CD40 ligand (CD154) in individuals with or at increased risk for insulin-dependent diabetes mellitus.

CD40 ligand (CD40L) regulates multiple phases of the humoral and cellular immune response through binding to CD40. Previous investigations have suggested that insulin-dependent diabetes (IDDM) in both humans and nonobese diabetic mice may be strongly influenced by similar immunoregulatory molecules. As persons with or at increased risk for the disease are characterized by a number of immunological abnormalities, including that of self-reactive autoantibody production (e.g. islet cell cytoplasmic autoantibodies), we analyzed the expression of CD40L on T lymphocytes (CD3+ cells) in a series of individuals with newly diagnosed IDDM (n = 11), nondiabetic relatives of IDDM probands at increased risk for the disease (n = 21; islet cell cytoplasmic autoantibodies positive; Juvenile Diabetes Foundation titer, > or = 20), and healthy controls (n = 13). Both phorbol myristate acetate (PMA)-stimulated and unstimulated peripheral blood mononuclear cells from study subjects were analyzed by flow cytometry with a series of phenotypic antibody markers (CD3, CD40L, and isotype controls). The kinetics of CD3 and CD40L expression on peripheral blood mononuclear cells under PMA-stimulated and unstimulated conditions were similar in the three study groups (6, 24, and 48 h; all P = NS). Similarly, unstimulated and PMA stimulated CD40L expressions (percentage of positive cells and level) on CD3+ cells from newly diagnosed IDDM patients and persons at increased risk for the disease were similar to those in healthy controls (6, 24, and 48 h; all P = NS). These findings do not support abnormal CD40L expression as the mechanism underlying the functional defect(s) in communication between T lymphocytes and antigen-presenting cells that allows for autoantibody production or the inability of individuals to regulate antiself immunity in IDDM.

Adolescent↗
PubMed1998

Construction and expression of a soluble form of human CD30 ligand with functional activity.

CD30 engagement in human lymphoid cells induces pleiotropic cellular responses that affect cellular viability and proliferation, cytokine production, and nuclear factor kappaB (NF-kappaB) nuclear translocation. Studies examining the molecular basis for this pleiotropism thus far have relied on the use of antibodies and cells transfected with CD30L to trigger CD30, two methods of receptor induction that present important limitations: antibodies are not physiological receptor-triggering molecules and CD30L transfectants induce high background intracellular signaling in the cells under study. We have generated and expressed a functional soluble human CD30L molecule (sCD30L/CD8alpha) comprised of the extracellular domain of human CD30L fused to the extracellular domain of the human CD8alpha chain. Immunoprecipitation and Western blot analysis of sCD30L/CD8alpha revealed the existence of at least two forms of sCD30L/CD8alpha, which exhibited molecular sizes consistent with the existence of monomeric and trimeric forms of the molecule. Binding analyses performed using a soluble CD30 fusion protein (sCD30/gamma1) confirmed the ability of sCD30L/CD8alpha to bind to CD30. Functionally, immobilized sCD30L/CD8alpha-induced cell death in the CD30-expressing lines Karpas-299 and HDLM-2 and reduced proliferative levels in Karpas-299; these effects were inhibitable by the addition of sCD30/gamma1. These studies demonstrate the utility of sCD30L/CD8alpha in characterizing the normal function of CD30L and CD30 and indicate the natural ability of soluble forms of CD30L to trimerize.

Blotting, Western↗
PubMed1998

Cellular immune responses to beta casein: elevated in but not specific for individuals with Type I diabetes mellitus.

Elevated cellular immune responses against the cows' milk protein beta casein have been reported in individuals with Type I diabetes mellitus, a finding supportive of the concept that cows' milk consumption may be causative for the disease. We analysed cellular immune reactivities against beta casein in newly-diagnosed Type I diabetic patients, their immediate autoantibody negative relatives, and unrelated healthy individuals in order to further elucidate the role of anti-beta casein immunity in the pathogenesis of Type I diabetes mellitus. Peripheral blood mononuclear cells were stimulated in vitro with various concentrations of three different beta casein preparations, control antigens (tetanus toxoid, mumps extract) and a mitogen (phytohemagglutinin). The frequency and/or mean simulation index of cellular proliferation against two of the beta casein preparations at high antigen concentrations (i.e. 10 or 50 microg/ml) were significantly higher in newly-diagnosed Type I diabetic subjects compared with autoantibody negative healthy control subjects. However, reactivities against beta casein in the Type I diabetic probands and their autoantibody negative relatives, individuals with a very low-rate of disease development, were almost identical. Cellular immune reactivities to other antigens were similar between the subject groups. In addition to indicating the need for appropriately matched subject populations (e.g. human leukocyte antigen (HLA) matched relatives) when analysing cellular immune responses, these findings support our previous contention that individuals genetically prone to autoimmunity may be deficient in forming tolerance to dietary antigens. However, the significance of anti-beta casein immunity as a specific causative factor in the pathogenesis of Type I diabetes mellitus remains unclear.

Adolescent↗
PubMed1998

The relationship between humoral and cellular immunity to IA-2 in IDDM.

Autoantibodies to the neuroendocrine protein insulinoma-associated protein 2 (IA-2), a member of the tyrosine phosphatase family, have been observed in individuals with or at increased risk for IDDM. Because this disease is thought to result from a T-cell-mediated autoimmune destruction of the insulin-producing pancreatic beta-cells, we analyzed humoral and cellular immune reactivity to this autoantigen to further define its role in the pathogenesis of IDDM. Peripheral blood mononuclear cells (PBMC) from individuals with newly diagnosed IDDM or at varying levels of risk for the disease were stimulated in vitro with the entire 42-kDa internal domain of IA-2 (amino acids 603-979), a series of control antigens (glutathionine-S-transferase, tetanus toxoid, Candida albicans, mumps, bovine serum albumin), and a mitogen (phytohemagglutinin). The frequency and mean stimulation index of PBMC proliferation against IA-2 was significantly higher in newly diagnosed IDDM subjects (14 of 33 [42%]; 3.8+/-4.5 at 10 microg/ml) and autoantibody-positive relatives at increased risk for IDDM (6 of 9 [66%]; 3.9+/-3.2) compared with autoantibody-negative relatives (1 of 15 [7%]; 1.8+/-1.0) or healthy control subjects (1 of 12 [8%]; 1.5+/-1.0). The frequencies of cellular immune reactivities to all other antigens were remarkably similar between each subject group. Sera from 58% of the newly diagnosed IDDM patients tested were IA-2 autoantibody positive. Despite investigations suggesting an inverse association between humoral and cellular immune reactivities against islet-cell-associated autoantigens, no such relationship was observed (rs=0.18, P=0.39) with respect to IA-2. These studies support the autoantigenic nature of IA-2 in IDDM and suggest the inclusion of cellular immune responses as an adjunct marker for the disease.

Adolescent↗
PubMed1997

Difference between lambs with chronic and mild dermatophilosis in frequency of alleles of CD3 gamma.

Southern blots prepared with DNA from 20 Merino lambs that previously had chronic dermatophilosis (chronic) and 20 lambs that previously had mild dermatophilosis lesions (resistant) were hybridised with DNA sequences of the genes for the T-cell receptor-beta (TCR beta), a TCR-associated peptide 'cluster designation 3 gamma chain' (CD3 gamma) and ovine Major Histocompatibility Complex class 1 (ov. MHC class 1). There was a significant difference in the incidence of an allele of CD3 gamma between the chronic and resistant lambs. No significant difference in the incidence of alleles of TCR beta or ov. MHC class 1 was detected.

Actinomycetales Infections↗