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D L Greiner

Publications and source records attributed to D L Greiner.

At least 73 records · Page 4Linked to original sources
PubMed1996

Abnormalities in the export and fate of recent thymic emigrants in diabetes-prone BB/W rats.

Abnormalities in postthymic T cell development in the BB/W rat model of autoimmune insulin-dependent diabetes mellitus (IDDM) result in part from a lymphopenia (lyp) gene defect. To better characterize these abnormalities, the phenotypes of T cells from diabetes-prone (DP) and diabetes-resistant (DR) coisogenic rats were analyzed by multiparameter flow immunocytometry (FCM). Marked decreases in the numbers of Thy1- RT6+ T cells, most of which are CD8+, were documented in DP rats by live-gating. Conversely, an approximately 3-fold increase was observed in the percentage of Thy1+ RT6- T cells, which normally serve as the precursors of both Thy1- RT6+ and Thy1- RT6- T cell subsets in rats. These results suggested that, at a minimum, an arrest in maturation of the Thy1+ precursors of RT6+ T cells occurs postthymically in DP rats. To determine more precisely the stage(s) in T cell development at which lymphopenia occurs, the export and fate of recent thymic emigrants (RTE's) and their immediate descendants in DP rats was traced after intrathymic (i.t.) labelling with fluorescein isothiocyanate (FITC). The results showed that in DP, as compared with DR, rats: 1) 5-fold fewer RTE's are exported from the thymus per 24 hr; 2) more than 80% of the RTE's are CD4+; 3) most of the immediate descendants of RTE's disappear from the peripheral lymphoid tissues within one week after export from the thymus; and 4) few of the descendants of the RTE's that do survive differentiate into RT6+ T cells. Staining with propidium iodide revealed that a significantly higher proportion of Thy1+ T cells in DP than in DR rats are in cycle (S/G2/M), thereby accounting for their disproportionately high numbers relative to RTE's. These results indicate that, in addition to defective thymic export, most of the immediate descendants of RTE's in DP rats undergo non-productive proliferation and death at the time (3-7 days postthymic) at which their counterparts in DR rats differentiate into Thy1- RT6+ T cells. The resulting deficiency of immunoregulatory T cells, acting in concert with defective intrathymic selection of effector T cell precursors, appears to conspire to markedly enhance the predisposition of DP rats to autoimmunity.

Animals↗
PubMed1996

Ontogeny and immunohistochemical localization of thymus-dependent and thymus-independent RT6+ cells in the rat.

RT6 is a cell surface alloantigen that identifies a regulatory subset of peripheral T cells in the rat. Diabetes-prone BB rats are deficient in peripheral RT6+ T cells and develop spontaneous autoimmune insulin-dependent diabetes mellitus. Diabetes-resistant BB rats have normal numbers of RT6+ T cells, and insulin-dependent diabetes mellitus can be induced in these animals by in vivo depletion of peripheral RT6+ cells. Athymic rats are also severely deficient in peripheral RT6+ T cells. Although very different with respect to the peripheral RT6+ cell compartment, normal, athymic, and diabetes-prone BB rats all generate RT6+ intestinal epithelial lymphocytes (IELs). The goal of these studies was to analyze the ontogeny of RT6+ IELs and peripheral lymphoid cells by in situ immunohistochemistry. We observed the following. 1) RT6+ IELs appear before alpha(beta) T-cell-receptor- expressing IELs in diabetes-prone BB, diabetes-resistant BB, and athymic WAG rats. 2) In vivo depletion of peripheral RT6+ T cells in diabetes-resistant BB rats using a cytotoxic monoclonal antibody is not accompanied by depletion of RT6+ IELs. 3) A population of RT6+ T-cell-receptor-negative IELs is present in normal, euthymic diabetes-resistant BB rats, constitutes a larger percentage of the euthymic but lymphopenic diabetes-prone BB rat IEL population, and is the predominant IEL phenotype in athymic WAG rats. These results suggest that RT6+ cells are composed of both thymus-dependent and thymus-independent cell subsets that have different developmental characteristics and may differ in function.

ADP Ribose Transferases↗
PubMed1996

Improved engraftment of human cord blood stem cells in NOD/LtSz-scid/scid mice after irradiation or multiple-day injections into unirradiated recipients.

Human lymphoematopoietic stem cells engraft in irradiated immunodeficient mice that are homozygous for the severe combined immunodeficiency (scid) mutation. Engraftment levels in C.B-17-scid/scid mice, however, have been low and transient, decreasing the utility of this model for investigation of the development potential and function of human stem cells. In the present study, we have used NOD/LtSz-scid/scid mice as recipients and human cord blood as a source of donor stem cells. Our results demonstrate that NOD/LtSz-scid/scid mice support approximately fivefold higher levels of human stem cell marrow engraftment than do C.B-17-scid/scid mice. Human CD34+ cells are present in the marrow of recipient mice, and the engrafted cells readily peripheralize to the circulation of the host. Terminal differentiation of the stem and progenitor cells into mature progeny is limited. Using a multiple-day injection protocol developed in mice, which allows engraftment of stem cells between congenic mice in the absence of irradiation preconditioning, we observed high levels of human cell engraftment in unirradiated NOD/LtSz-scid/scid recipients after three or five consecutive-day injections. These results demonstrate that NOD/LtSz-scid/scid mice support high levels of human stem cell engraftment and that xenogeneic lymphohematopoietic stem cells can engraft in unirradiated hosts without the need for ablative reconditioning. This model will be useful for the in vivo investigation of human stem cells and for the preclinical analysis of human stem cells for transplantation.

Animals↗
PubMed1995

Survival of mouse pancreatic islet allografts in recipients treated with allogeneic small lymphocytes and antibody to CD40 ligand.

Combined treatment with allogeneic small lymphocytes or T-depleted small lymphocytes plus a blocking antibody to CD40 ligand (CD40L) permitted indefinite pancreatic islet allograft survival in 37 of 40 recipients that differed from islet donors at major and minor histocompatibility loci. The effect of the allogeneic small lymphocytes was donor antigen-specific. Neither treatment alone was as effective as combined treatment, although anti-CD40L by itself allowed indefinite islet allograft survival in 40% of recipients. Our interpretation is that small lymphocytes expressing donor antigens in the absence of appropriate costimulatory signals are tolerogenic for alloreactive host cells. Anti-CD40L antibody may prevent host T cells from inducing costimulatory signals in donor lymphocytes or islet grafts.

Animals↗
PubMed1995

Multiple defects in innate and adaptive immunologic function in NOD/LtSz-scid mice.

The scid mutation was backcrossed ten generations onto the NOD/Lt strain background, resulting in an immunodeficient stock (NOD/LtSz-scid/scid) with multiple defects in adaptive as well as nonadaptive immunologic function. NOD/LtSz-scid/scid mice lack functional lymphoid cells and show little or no serum Ig with age. Although NOD/(Lt-)+/+ mice develop T cell-mediated autoimmune, insulin-dependent diabetes mellitus, NOD/LtSz-scid/scid mice are both insulitis- and diabetes-free throughout life. However, because of a high incidence of thymic lymphomas, the mean lifespan of this congenic stock is only 8.5 mo under specific pathogen-free conditions. After i.v. injection of human CEM T-lymphoblastoid cells, splenic engraftment of these cells was fourfold greater in NOD/LtSz-scid/scid mice than in C.B17/Sz-scid/scid mice. Although C.B-17Sz-scid/scid mice exhibit robust NK cell activity, this activity is markedly reduced in both NOD/(Lt-)+/+ and NOD/LtSz-scid/scid mice. Presence of a functionally less mature macrophage population in NOD/LtSz-scid/scid vs C.B-17Sz-scid/scid mice is indicated by persistence in the former of the NOD/Lt strain-specific defect in LPS-stimulated IL-1 secretion by marrow-derived macrophages. Although C.B-17Sz-scid/scid and C57BL/6Sz-scid/scid mice have elevated serum hemolytic complement activity compared with their respective +/+ controls, both NOD/(LtSz-)+/+ and NOD/LtSz-scid/scid mice lack this activity. Age-dependent increases in serum Ig levels (> 1 micrograms/ml) were observed in only 2 of 30 NOD/LtSz-scid/scid mice vs 21 of 29 C.B-17/Sz-scid/scid animals. The multiple defects in innate and adaptive immunity unique to the NOD/LtSz-scid/scid mouse provide an excellent in vivo environment for reconstitution with human hematopoietic cells.

Agammaglobulinemia↗
PubMed1995

High levels of human peripheral blood mononuclear cell engraftment and enhanced susceptibility to human immunodeficiency virus type 1 infection in NOD/LtSz-scid/scid mice.

Inbred C.B-17-scid/scid mice accept human peripheral blood mononuclear cell (PBMC) xenografts and are susceptible to human immunodeficiency virus type 1 (HIV-1) infection, but low levels of PBMC engraftment impede use of this system in HIV research. This report describes the effect of host strain background on human PBMC engraftment and HIV infectivity in scid mice. Back-crossing the scid mutation to the NOD/Lt strain (designated NOD/LtSz-scid/scid) increased the percentage of engrafted human PBMC in recipient spleens by 5- to 10-fold compared with that in C.B-17-scid/scid stock. Four weeks after human PBMC-injected mice were infected with HIV-1, 79% of NOD/LtSz-scid/scid spleens harbored replicating virus compared with only 39% of spleens in C.B-17-scid/scid mice. The NOD/LtSz-scid/scid mouse may provide a useful small animal model for studies of HIV-1.

Animals↗
PubMed1995

Emv30null NOD-scid mice. An improved host for adoptive transfer of autoimmune diabetes and growth of human lymphohematopoietic cells.

When used as hosts in passive transfer experiments, a stock of NOD/Lt mice congenic for the severe combined immunodeficiency (scid) mutation have provided great insight to the contributions of various T-cell populations in the pathogenesis of autoimmune insulin-dependent diabetes mellitus (IDDM). Moreover, NOD-scid mice support higher levels of human lymphohematopoietic cell growth than the C.B-17-scid strain in which the mutation originated. However, the ability to perform long-term lymphohematopoietic repopulation studies in the NOD-scid stock has been limited by the fact that most of these mice develop lethal thymic lymphomas beginning at 20 weeks of age. These thymic lymphomas are characterized by activation and subsequent genomic reintegrations of Emv30, an endogenous murine ecotropic retrovirus unique to the NOD genome. To test the role of this endogenous retrovirus in thymomagenesis, we produced a stock of Emv30null NOD-scid mice by congenic replacement of the proximal end of chromosome 11 with genetic material derived from the closely related NOR/Lt strain. Thymic lymphomas still initiate in Emv30null NOD-scid females, but their rate of progression is significantly retarded since the frequency of tumors weighing between 170 and 910 mg at 25 weeks of age was reduced to 20.8% vs. 76.2% in Emv30% segregants. The thymic lymphomas that did develop in Emv30null NOD-scid mice were not characterized by a compensatory increase in mink cell focus-forming proviral integrations, which initiate thymomagenesis in other susceptible mouse strains. Significantly, the ability of standard NOD T-cells to transfer IDDM to the Emv30null NOD-scid stock was not impaired.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

DR-BB rat thymus contains thymocyte populations predisposed to autoreactivity.

We have induced autoimmune insulin-dependent diabetes mellitus (IDDM) in athymic WAG rats by transfusing thymocytes from histocompatible phenotypically normal rats of the DR-BB strain. DR-BB rats rarely develop spontaneous IDDM, but readily become hyperglycemic if depleted in vivo of regulatory T-cells that express the RT6.1 maturational alloantigen. Successful adoptive transfer of IDDM by DR-BB thymocytes required that the athymic recipients be depleted of emerging populations of donor-origin RT6.1+ T-cells. Thymocytes from both normal and RT6-depleted diabetic DR donors were equally capable of transferring autoimmunity. In contrast, thymocytes from normal histocompatible YOS rats failed to transfer IDDM. The autoreactive potential of DR-BB rat thymocytes was minimal from birth to 4 weeks of age and then increased substantially at 8-9 weeks of age. These results demonstrate that the DR-BB rat thymus harbors abnormal cell populations predisposed to autoreactivity. The data localize the developmental defect leading to diabetes in the BB rat to an abnormal intrathymic selection process.

Animals↗
PubMed1995

Improved engraftment of human spleen cells in NOD/LtSz-scid/scid mice as compared with C.B-17-scid/scid mice.

T and B lymphocyte-deficient mice homozygous for the severe combined immunodeficiency (SCID) mutation can be immunologically engrafted with human lymphocytes. However, low levels of human peripheral blood mononuclear cell engraftment are commonly observed, impeding full use of this model. We now demonstrate that strain background in mice homozygous for the scid mutation is a strong determinant of levels of human lymphocyte engraftment. NOD/LtSz-scid/scid mice support higher levels of engraftment of both human spleen and peripheral blood mononuclear cells than do C.B-17-scid/scid mice. We observed, using human spleen cell injected scid mice, 1), high levels of engraftment of the host peripheral lymphoid tissues with human CD45+ (leukocytes), CD3+ (T cells), CD4+ (helper/inducer), and CD8+ (suppressor/cytotoxic) lymphoid cells for up to 24 weeks in NOD/LtSz-scid/scid mice; 2), migration of high numbers of human lymphocytes to peripheral lymphoid and nonlymphoid organs in NOD/LtSz-scid/scid, but not in C.B-17-scid/scid mice; 3), higher levels of serum immunoglobulin of human origin in NOD/LtSz-scid/scid mice than in C.B-17-scid/scid mice; 4), histological lesions characteristic of human anti-mouse xenoreactivity in NOD/LtSz-scid/scid mice; and 5), human origin antibodies against filarial antigens after engraftment with native human spleen cells. The use of NOD/LtSz-scid/scid mice as recipients to achieve significantly enhanced human lymphopoietic cell engraftment will now enable human immunity to be more easily studied in animal models.

Animals↗
PubMed1995

B lymphocytes are not required for murine resistance to the human filarial parasite, Brugia malayi.

Immunocompetent mice are resistant to the growth and development of human lymphatic filarial parasites, including the aperiodic strain of Brugia malayi. We have recently established that mice homozygous for the severe combined immunodeficiency (scid) mutation, and therefore deficient in both T and B lymphocytes, are permissive for infection. This observation suggests that components of the adaptive (antigen-specific) immune system are obligate requirements for murine resistance to B. malayi. In order to determine more precisely the component of the immune system that mediates murine resistance to B. malayi, we have used mouse strains in which individual genes involved in the maturation of specific components of the immune system have been disrupted by homologous recombination. In previous studies, we demonstrated that mice that lack either major histocompatibility (MHC) class I restricted, CD8+ T lymphocytes (beta 2-microglobulin knockout mice; beta 2M-/-) or CD4+ T lymphocytes (CD4 knockout mice; CD4-/-) are as resistant to B. malayi as intact mice. In the current study, we have used mice in which the membrane exon of the immunoglobulin (Ig) mu (heavy chain) constant region gene segment has been disrupted by homologous recombination. These mice cannot develop mature B lymphocytes and lack serum Ig. We demonstrate that such "B-less" mice are completely resistant to B. malayi. These data, taken in combination with the observation that T-cell-deficient athymic mice homozygous for the nu (nude) mutation are fully permissive for infection, suggest that B lymphocytes and their products are neither required nor sufficient to mediate resistance to B. malayi.

Animals↗
PubMed1994

Mercury-induced renal autoimmunity in BN-->LEW.1N chimeric rats.

Repeated exposure to relatively low doses of mercuric chloride causes a variety of autoimmune responses in rats of the Brown Norway (BN) strain. These animals experience a membranous glomerulonephritis, characterized by the production of autoantibodies to renal antigens (e.g., laminin) and proteinuria. In contrast, Lewis (LEW) rats are "resistant" to the autoimmune effects of mercury. Despite extensive investigations, the mechanisms of immunoregulation in this animal model are still unknown. RT6+ T lymphocytes may have a regulatory role in both BN and LEW rats. This hypothesis is suggested by our finding of a mercury-associated decrease of RT6+ T cells in lymph nodes of BN rats exposed to mercury and the lack of such effect in similarly treated LEW rats. In the present report we show that congenic LEW.1N or BN.1L had no renal autoimmune disease after treatment with HgCl2. FCM analysis of mercury-treated LEW.1N revealed that RT6.1+ T lymphocytes were significantly decreased in both spleen and lymph nodes of these animals. Experimental depletion of RT6+ T cells (by monoclonal antibody treatment or gamma irradiation) in LEW.1N and BN.1L rats did not favor the induction of renal autoimmunity after exposure to mercury. On the other hand, BN-->LEW.1N chimeras (obtained by adoptive transfer of BN lymphocytes into gamma-irradiated LEW.1N rats) experienced autoimmune responses to kidney antigens when treated with HgCl2. They had autoantibodies to laminin and linear binding of immunoglobulins in their kidneys as well as a decreased percentage of RT6.2+ T lymphocytes in cervical lymph nodes. Therefore, the different components of this experimental model can now be dissected using various types of BN-->LEW.1N chimeras, obtained by the adoptive transfer of purified T cell subsets.

ADP Ribose Transferases↗
PubMed1994

Evidence that intrathymic islet transplantation does not prevent diabetes or subsequent islet graft destruction in RT6-depleted, diabetes-resistant BioBreeding/Worcester rats.

Pancreatic islet allografts transplanted intrathymically are accepted and restore normoglycemia in streptozotocin-diabetic rats given one injection of antilymphocyte serum. Intrathymic allografts similarly restore normoglycemia in diabetes-prone (DP) Bio-Breeding (BB) rats that have developed spontaneous autoimmune diabetes. Intrathymic islets also reduce the frequency of subsequent diabetes when transplanted prophylactically into young DP rats. These findings suggest that intrathymic transplantation can prevent not only allograft rejection, but also the appearance and recurrence of autoimmune tissue destruction. To explore these hypotheses further, we attempted both to confirm previous studies and to extend them to another model of autoimmune diabetes, the RT6-depleted diabetes-resistant (DR) BB rat. Fewer than 1% of DR-BB rats develop spontaneous diabetes, but most become hyperglycemic after in vivo immune elimination of RT6+ T cells. Using the protocols described in the literature, we observed the following: (1) Consistent with previous reports, intrathymic islet allografts survived indefinitely in streptozotocin-diabetic, antilymphocyte serum-treated, non-BB recipient rats. (2) Consistent with previous reports, intrathymic islet grafts produced long-term normoglycemia in diabetic DP-BB rats and also reduced the frequency of spontaneous diabetes in young animals transplanted prophylactically. (3) In contrast, intrathymic islets (iso- and allografts) neither prevented nor reversed diabetes in RT6-depleted DR rats. We hypothesize that intrathymic islet grafts survive in DP-BB rats because they are lymphopenic and immunocompromised, whereas immunocompetent diabetic DR rats successfully recapitulate the autoimmune disease process. Although intrathymic allograft transplantation is postulated to induce a state of tissue-specific tolerance, our results indicate that this tolerant state may not extend to autoimmune destruction of either isografts or allografts.

ADP Ribose Transferases↗
PubMed1994

Localization of prothymocytes from wild-type and viable motheaten mice following intravenous injection into irradiated adoptive recipients.

Bone marrow cells from viable motheaten (me(v)) mutant mice fail to repopulate the thymus of irradiated recipients upon i.v. adoptive transfer. This defect can be corrected by the addition of wild-type marrow to the me(v)/me(v) marrow prior to i.v. injection. The present study focused on the nature of this apparent defect in me(v)/me(v) prothymocyte activity. We established an adoptive transfer assay system that facilitated the investigation of the migration patterns of wild-type and me(v)/me(v) marrow prothymocytes in adoptive recipients. Wild-type prothymocytes were found to seed the thymus of recipients as early as 1 day after i.v. injection. This early wave of prothymocyte seeding peaked at 4 days and diminished to undetectable levels at 6 days postinjection. After an interval of no detectable wild-type precursor activity in the thymus of primary recipients, a second wave of activity was observed on Day 15. This second wave resulted in permanent engraftment and persisted throughout the observation period. In contrast, only one initial wave of me(v)/me(v) prothymocyte seeding occurred in the recipient thymus. Detection of mev/mev precursors in the recipient's thymus was dependent upon the coinjection of wild-type marrow cells. These results suggest that me(v)/me(v) prothymocytes initially seed to the thymus of adoptive recipients, but fail to proliferate and/or differentiate due to a defect in marrow-derived intrathymic accessory cell activity.

Animals↗
PubMed1994

CD4+ T-lymphocytes are not required for murine resistance to the human filarial parasite, Brugia malayi.

Immunocompetent mice are nonpermissive for the development and maturation of the human filarial parasite, Brugia malayi. We and others have shown that the absence of T-lymphocytes, alone or in combination with B-lymphocytes, renders mice permissive to infection. In a previous study, we showed that mice lacking CD8+ T-lymphocytes are also completely nonpermissive for B. malayi, indicating that CD8+ T-lymphocytes are not an obligate requirement for resistance. In the present study, we have examined the role of CD4+ T-lymphocytes in resistance to filarial infection using two experimental systems. In the first, we used an anti-CD4 monoclonal antibody to deplete CD4+ T-cells in vivo in immunocompetent BALB/c mice. In the second system, we used mutant mice in which the gene encoding the CD4 antigen had been disrupted by homologous recombination, resulting in a lack of CD4+ T-cells. Challenge of either the anti-CD4 antibody depleted BALB/c mice or CD4 knockout mice with B. malayi infective-stage larvae demonstrated that mice lacking CD4+ T-lymphocytes were resistant to infection. These data indicate that CD4+ T-cells are not an obligate requirement for murine resistance to B. malayi.

Animals↗
PubMed1994

Adoptive transfer of autoimmune diabetes mellitus to athymic rats: synergy of CD4+ and CD8+ T cells and prevention by RT6+ T cells.

We describe the induction and prevention of autoimmune insulin dependent diabetes mellitus (IDDM), and its pathological substrate, insulitis, in congenitally athymic nude rats following injections of major histocompatibility complex (MHC) compatible lymph node T cells. The cells capable of adoptive transfer of autoimmunity were obtained from diabetes resistant (DR) BB rats that had been rendered hyperglycemic by in vivo depletion of the RT6+ regulatory T cell subset. We first established that our adoptive transfer assay system is cell dose- and time dependent and therefore amenable to quantitative analysis. It was also observed that both CD4+ and CD8+ T cells are required for efficient transfer of autoimmunity. The data indicate that, as in the NOD mouse, a synergistic interaction between CD4+ and CD8+ T cells is important for beta cell destruction. Finally, we demonstrated that the admixture of equal numbers of lymph node T cells, 60% of which were RT6+, from intact, non-diabetic DR rats prevented the adoptive transfer of IDDM mediated by diabetogenic T cells from RT6-depleted DR-BB rats. We conclude that an equilibrium between autoreactive and regulatory cells determines the expression of autoimmunity in the DR-BB rat and in the adoptive transfer of diabetes in quantitative analytical systems.

Animals↗
PubMed1994

Maternal influence on susceptibility of offspring to Brugia malayi infection in a murine model of filariasis.

We have used the severe combined immunodeficient C.B-17-scid/scid mouse to investigate the influences of maternal immune status and parasite burden on the susceptibility (or resistance) of offspring to infection with the human filarial parasite, Brugia malayi. C.B-17-scid/scid mice are permissive for infection while immunocompetent C.B-17(-)+/+ mice are uniformly resistant. Reciprocal matings of C.B-17-scid/scid and C.B-17(-)+/+ mice were performed. The C.B-17-scid/scid females were either naive or infected with Brugia malayi. The resulting immunocompetent C.B-17-scid/+ and C.B-17(-)+/scid progeny were challenged at weaning with an intraperitoneal injection of Brugia malayi third stage larvae known to produce patent infection in > 95% of C.B-17-scid/scid mice. We observed that 40.0%l (34/85) of the immunocompetent offspring of C.B-17-scid/scid females x C.B-17(-)+/+ males were permissive for the growth and development of Brugia malayi larvae to adults. No difference was observed in susceptibility to infection between the progeny of infected or uninfected C.B-17-scid/scid mothers mated with C.B-17(-)+/+ fathers, arguing against acquired immunological tolerance to the parasite in the former. In marked contrast, only 4.8% (2/42) of the heterozygous progeny of wild type C.B-17(-)+/+ females mated with C.B-17-scid/scid males were permissive. These observations document conversion of a 'resistant' phenotype to a 'susceptible' phenotype by manipulation of maternal immune status and provide clear evidence of maternal influence on offspring susceptibility to infection with Brugia malayi.

Alleles↗