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Biomedical subjects

C J Kelly

Publications and source records attributed to C J Kelly.

At least 109 records · Page 6Linked to original sources

Effector T cell differentiation in experimental interstitial nephritis. I. The development and modulation of effector lymphocyte maturation by I-J+ regulatory T cells.

Because mice susceptible to interstitial nephritis use different effector T cells than nonsusceptible mice, we analyzed the differentiation process of the effector T cell repertoire by using an in vitro culture technique. In the presence of helper T lymphocytes, accessory cells, IL 2, tubular antigen, and precursor effector cells, both Lyt-2+ nephritogenic effector cells and L3T4+ nonnephritogenic effector cells can be initially induced in both susceptible and nonsusceptible strains within 3 days of culture. In nonsusceptible mice, however, the Lyt-2+ nephritogenic cell is inhibited from further development and disappears, whereas in susceptible mice, its presence is preserved with a resulting effect of tissue destruction. This selection of effector T cell preference is regulated by I-J+ T lymphocytes which are co-functionally expressed with effector cell expansion. Unlike precursor effector lymphocytes, however, the maturation of the regulatory process requires a subset of I-J+ accessory cells and structurally intact tubular antigen. Our findings indicate, therefore, that both susceptible and nonsusceptible mice have the potential for the expression of interstitial nephritis, but nonsusceptible mice are formally protected from autoimmunity by the regulation of lymphocyte preference.

Animals↗

Contrasuppression in autoimmunity. Abnormal contrasuppression facilitates expression of nephritogenic effector T cells and interstitial nephritis in kdkd mice.

We have used the murine model of spontaneous autoimmune interstitial nephritis in kdkd mice to examine the importance of abnormal immunoregulation in the expression of disease. T cells from naive congenic CBA/Ca mice suppress both histologic renal injury in the kdkd strain as well as the DTH reactivity to CBA/Ca renal tubular antigens mediated by lymphocytes from nephritic kdkd mice. These antigen-specific suppressor T cells are Lyt-2+, L3T4+, I-Jk+, genetically dominant and I-Jk restricted. Unfractionated spleen cells from young, prenephritic kdkd mice also demonstrate such suppressor function. Shortly preceding disease onset, however, net suppression is functionally bypassed by emergent contrasuppressor T cells. These regulatory cells are also Lyt-2+ and I-Jk+, and adhere both to the Vicia Villosa lectin and CBA/Ca TBM. By admixing these contrasuppressor cells with spleen cells from non-disease-prone CBA/Ca mice we were able to demonstrate the presence of DTH-reactive and nephritogenic effector cells in the latter population. Such nephritogenic effector cells could also be simply demonstrated after depletion of the suppressor cells with anti-I-Jk mAbs and complement. These findings support a role for contrasuppressor cells in the abrogation of tolerance to parenchymal self-antigens.

Age Factors↗

Therapeutic immune regulation in experimental interstitial nephritis with suppressor T cells and their soluble factors.

The therapeutic application of immune regulation and suppressor T cells to the control and modulation of autoimmune disease is an area of growing experimental interest. Our group has been studying experimental interstitial nephritis, both to better understand the disease process itself and to test immunoregulatory strategies for their inhibitory and protective effects. This report gives a brief overview of this work.

Animals↗

Prostaglandin E1 inhibits effector T cell induction and tissue damage in experimental murine interstitial nephritis.

Immunosuppressive effects of E-series prostaglandins have been demonstrated in many in vitro assays of immune responsiveness as well as in autoimmune diseases. To explore the mechanisms underlying prostaglandin E1 (PGE1)-associated immunosuppression in autoimmunity, we treated SJL mice immunized to produce immune-mediated interstitial nephritis with PGE1, PGF2 alpha, or vehicle alone. Mice receiving PGE1 treatment do not develop interstitial nephritis, nor do they display delayed-type hypersensitivity (DTH) to the immunizing renal tubular antigen preparation. The observed immunosuppression is critically dependent on PGE1 administration during the period of effector T cell induction. We therefore investigated the effect of PGE1 on the in vitro induction of DTH effector T cells reactive to renal tubular antigens (SRTA). PGE1 inhibits effector T cell induction in a dose-dependent, reversible manner, but has no inhibitory effect on fully differentiated DTH effector cells or SRTA-reactive cell lines. The PGE1 effect is indirect and mediated via nonspecific suppressor lymphokines. This suppression can be overcome by recombinant interleukin 1 (IL-1), which suggests a mechanism related to either diminished IL-1 secretion or target cell sensitivity to IL-1.

Alprostadil↗

Immunoregulation in experimental interstitial nephritis: immunization with renal tubular antigen in incomplete Freund's adjuvant induces major histocompatibility complex-restricted, OX8+ suppressor T cells which are antigen-specific and inhibit the expression of disease.

We utilized a model of experimental interstitial nephritis induced by renal tubular antigen in complete Freund's adjuvant to examine a mechanism of immunologic tolerance produced by priming immunization with tubular antigen in incomplete Freund's adjuvant. Brown Norway rats primed with tubular antigen in incomplete adjuvant do not develop significant nephritis after challenge with antigen in complete adjuvant, and this tolerance can be transferred to naive recipients with donor T cells. These T cells also specifically suppress a delayed-type hypersensitivity response to soluble tubular antigen in recipients immunized to produce disease. This suppression is MHC-restricted and is mediated by OX8+ T cells which bind antigen and bear idiotypes cross-reactive with those on antibodies eluted from the tubular basement membrane. Despite the suppression of histologic disease, tolerized animals were able to produce significant titers of antibodies to tubular basement membrane. Our findings demonstrate an additional strategy for altering the natural history of immune-mediated renal disease, and further refine the characterization of the suppressive effect produced by incomplete Freund's adjuvant.

Animals↗

Acute renal failure in sickle-cell disease.

Two patients with reversible acute oligoanuric renal failure in the setting of sickle-cell crisis are presented. The renal failure could not be attributed to volume depletion, urinary tract obstruction, or exogenous nephrotoxins. There were several features in each case that suggested the presence of nontraumatic rhabdomyolysis. The possible role of pigmenturia in the pathogenesis of the reversible renal failure in sickle-cell crisis is discussed.

Acute Kidney Injury↗

Experimental strategies for the study of cellular immunity in renal disease.

This overview has examined some of the current experimental options available for the study of cellular immunity in the immunopathogenesis of renal disease. T cell immunity, where it has been examined, seems to have a particularly pivotal role in orchestrating and regulating functional patterns of renal injury. The use of the research methods presented here for the study of cell-mediated interactional events in kidney disease, however, has lagged behind similar efforts in other organ systems. We hope, therefore, this report will serve to stimulate and strengthen further interest in the cell biology of the nephritogenic immune response.

Animals↗

Spontaneous interstitial nephritis in kdkd mice. II. Characterization of a tubular antigen-specific, H-2K-restricted Lyt-2+ effector T cell that mediates destructive tubulointerstitial injury.

In this report, we have examined the effector T cell repertoire in the spontaneous interstitial nephritis of kdkd mice. Lymph node cells from nephritic kdkd mice are capable of transferring this disease into thymectomized, irradiated, and bone marrow-reconstituted CBA/Ca recipients. CBA/Ca mice do not spontaneously develop interstitial nephritis and are normally resistant to the adoptive transfer of nephritic cells, a resistance that in the short term can be attenuated with low-dose cyclophosphamide. We therefore used delayed-type hypersensitivity responses and direct transfer of immune cells under the renal capsule to characterize nephritogenic effector cells from kdkd donor mice. Lyt-2+, L3T4- T cells from the peripheral lymphoid organs of nephritic kdkd mice, after adoptive transfer into cyclophosphamide-pretreated CBA/Ca recipients, mediate an antigen-specific delayed-type hypersensitivity response to renal tubular basement membrane antigens. These cells are restricted by gene products in H-2Kk; they are also present in nephritic, but not in control kidneys. We have also observed this same phenotypic subpopulation of kdkd lymphocytes mediate a destructive interstitial renal lesion within 7 days of being placed under the kidney capsule of CBA/Ca mice. These findings suggest that T lymphocytes reactive to a parenchymal tubular antigen are of substantial importance in the development of spontaneous interstitial nephritis in kdkd mice.

Animals↗

Tolerance to parenchymal self. Regulatory role of major histocompatibility complex-restricted, OX8+ suppressor T cells specific for autologous renal tubular antigen in experimental interstitial nephritis.

BN rats develop interstitial nephritis after immunization with rabbit, but not rat renal tubular antigen. Using RT1n rat strains that differentially express tubular antigen, we investigated the unresponsiveness of BN rats to BN tubular antigen (BN-TBM) using delayed-type hypersensitivity (DTH) responses to BN-TBM as a measure of cell-mediated immunity. Our results indicate that rat strains expressing tubular antigen respond to immunization with BN-TBM with the clonal expansion of antigen-specific, cyclophosphamide-sensitive, OX8+, MHC-restricted suppressor T cells. Such suppression appears to be relevant to the maintenance of tolerance to parenchymal self, since chronic cyclophosphamide therapy abrogates suppression and results in significant interstitial nephritis.

Animals↗

Antiidiotypic immunity in interstitial nephritis. II. Rats developing anti-tubular basement membrane disease fail to make an antiidiotypic regulatory response: the modulatory role of an RT7.1+, OX8- suppressor T cell mechanism.

Antiidiotypic immunity can successfully inhibit the development of antitubular basement membrane (alpha TBM) disease that produces interstitial nephritis. Rats normally immunized to produce disease, however, do not develop this regulatory and protective antiidiotypic effect. The failure to see such a regulatory response is functionally related to the influence of a nonspecific, RT7.1+, OX8-suppressor T cell that appears shortly after immunization. While this suppressor cell system can partially reduce the intensity of disease, it also limits the host's ability to specifically regulate the alpha TBM immune response and, hypothetically, leaves the disease process in an operationally active mode.

Animals↗

Effect of alpha-methylphenylalanine and phenylalanine on brain polyribosomes and protein synthesis.

A chronic hyperphenylalanemia was effectively produced in developing mice by daily administrations of phenylalanine (2 mg/g body wt) and a phenylalanine hydroxylase inhibitor alpha-methyl-D,L-phenylalanine (0.43 mg/g body wt). The presence of alpha-methylphenylalanine in newborn mice inhibited 65-70% of hepatic phenylalanine hydroxylase activity within 12 h. Since this maximum inhibition persisted for 24 h or longer, decreased enzyme activity was maintained by daily administrations. Whereas concentrations of phenylalanine increased approximately 40-fold in both plasma and brain following injection of alpha-methylphenylalanine and phenylalanine, plasma levels of tyrosine were not altered significantly. Concomitant with changes in phenylalanine concentrations we observed the brain polyribosomes' disaggregation, which reached a maximum 3 h after injection and persisted as long as 18 h. Polyribosomes did not become refractory to as many as 10 daily injections of alpha-methylphenylalanine and phenylalanine. In addition to polyribosome disaggregation, chronic hyperphenylalanemia reduced the rates of polypeptide chain elongation on polyribosomes isolated from brain homogenates.

Animals↗

Effects of p-chlorophenylalanine and alpha-methylphenylalanine on amino acid uptake and protein synthesis in mouse neuroblastoma cells.

The phenylalanine analogues p-chlorophenylalanine and alpha-methylphenylalanine were used to inhibit phenylalanine hydroxylase in animal models for phenylketonuria. The present report examines the affects of these analogues on the metabolism of neuroblastoma cells. p-Chlorophenylalanine inhibited growth and was toxic to neuroblastoma cells. Although in vivo this analogue increased cell monoribosomes by 42%, it did not significantly affect poly(U)-directed protein synthesis in vitro. P-Chlorophenylalanine did not compete with phenylalanine or tyrosine for aminoacylation of tRNA and was therefore not substituted for those amino acids in nascent polypeptides. The initial cellular uptake of various large neutral amino acids was inhibited by this analogue but did not affect the flux of amino acids already in the cell; this suggested that an alteration of the cell's amino acid pools was not responsible for the cytotoxicity of the analogues. In contrast with p-chlorophenylalanine, alpha-methylphenylalanine did not exert these direct toxic effects because the administration of alpha-methylphenylalanine in vivo did not affect brain polyribosomes and a comparable concentration of this analogue was neither growth inhibitory nor cytotoxic to neuroblastoma cells in culture. The suitability of each analogue as an inhibitor of phenylalanine hydroxylase in animal models for phenylketonuria is discussed.

Amino Acids↗

Pharmacokinetic considerations in evaluating the effects of tetrahydrouridine on 5-azacytidine chemotherapy in L1210 leukemic mice.

The pharmacokinetics of 5-azacytidine (5-azaCR) and tetrahydrouridine (THU) were considered in evaluating the effect of THU on chemotherapy with 5-azaCR in L1210 leukemia mice. The administration of three different dose levels of THU and 5-azaCR ip in either a 6- or 72-hour infusion gave minimal increases in therapeutic effect. At the high-dose combinations (except in the 72-hour infusion), THU appeared to enhance toxicity. Toxicity, however, occurred only after exceeding a theoretic plasma concentration for 5-azaCR of 61 microgram/ml. THU was effective in increasing the excretion of 5-azaCR by sixfold and in altering its urinary metabolites when given simultaneously with or up to 1 hour prior to 5-azaCR.

Animals↗

Radioactive labelling of ribosomal proteins with reductive alkylation and its use in studying ribosome-cytosol interactions.

Mouse brain ribosomes were radioactively labelled by a cell-free reductive alkylation reaction with NaBH4 and [14C]formaldehyde. The radioactivity was largely associated with ribosomal proteins, but little, if any, of the rRNA was radioactive after the alkylation procedure. Both ribosomal structural proteins and loosely associated components were successfully labelled by this procedure. The sedimentation properties of the ribosomes were unaltered and their ability to carry out poly(U)-directed protein synthesis, although decreased, was largely retained. Incubation of 14C-labelled ribosomes with brain cytosol resulted in a 17% loss of radioactivity, although treatment of the ribosomes with 1.0 m-KCl to remove the loosely associated factors rendered the ribonucleoprotein particles resistant to cytosol effects. The ribosome-cytosol interactions did not appear to be related to an exchange process, since the released radioactivity was largely degraded to acid-soluble material. In addition, the incubation of native ribosomes with brain cytosol resulted in an almost complete loss in the ability of the ribosomes to participate in cell-free protein synthesis.

Alkylation↗

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Fees, Medical↗