R|S Atlas: Identifying existing cohort study data resources to accelerate epidemiological research on the influence of religion and spirituality on human health

OBJECTIVE

Many studies have documented significant associations between religion and spirituality (R/S) and health, but relatively few prospective analyses exist that can support causal inferences. To date, there has been no systematic analysis of R/S survey items collected in US cohort studies. We conducted a systematic content analysis of all surveys ever fielded in 20 diverse US cohort studies funded by the National Institutes of Health (NIH) to identify all R/S-related items collected from each cohort's baseline survey through 2014.

DESIGN

An R|S Ontology was developed from our systematic content analysis to categorise all R/S survey items identified into key conceptual categories. A systematic literature review was completed for each R/S item to identify any cohort publications involving these items through 2018.

RESULTS

Our content analysis identified 319 R/S survey items, reflecting 213 unique R/S constructs and 50 R|S Ontology categories. 193 of the 319 extant R/S survey items had been analysed in at least one published paper. Using these data, we created the R|S Atlas (https://atlas.mgh.harvard.edu/), a publicly available, online relational database that allows investigators to identify R/S survey items that have been collected by US cohorts, and to further refine searches by other key data available in cohorts that may be necessary for a given study (eg, race/ethnicity, availability of DNA or geocoded data).

CONCLUSIONS

R|S Atlas not only allows researchers to identify available sources of R/S data in cohort studies but will also assist in identifying novel research questions that have yet to be explored within the context of US cohort studies.

Measuring health-care delays among privately insured patients with tuberculosis in the USA: an observational cohort study

BACKGROUND

A high index of suspicion is needed to initiate appropriate testing for tuberculosis due to its protean symptoms, yet health-care providers in low-incidence settings are becoming less familiar with the disease as rates decline. We aimed to estimate delays in tuberculosis diagnosis and treatment at the US national level between 2008 and 2016.

METHODS

In this retrospective observational cohort study, we repurposed private insurance claims data provided by Aetna (Connecticut, USA), to measure health-care delays in tuberculosis diagnosis in the USA in 2008-16. Active tuberculosis was determined by diagnosis codes and the filling of anti-tuberculosis treatment prescriptions. Health-care delays were defined as the duration between the first health-care visit for a tuberculosis symptom and the initiation of anti-tuberculosis treatment. We assessed if delays varied over time, and by patient and system variables, using multivariable regression. We estimated household tuberculosis transmission and respiratory complications after treatment initiation.

FINDINGS

We confirmed 738 active tuberculosis cases (incidence 1·45 per 100 000 person-years) with a median health-care delay of 24 days (IQR 10-45). Multivariable regression analysis showed that longer delays were associated with older age (8·4% per 10 year increase [95% CI 4·0 to 13·1]; p<0·0086) and non-HIV immunosuppression (19·2% [15·1 to 60·0]; p=0·0432). Presenting with three or more symptoms was associated with a shorter delay (-22·5% [-39·1 to -2·0]; p=0·0415), relative to presenting with one symptom, as did use of chest imaging (-24·9% [-37·9 to -8·9]; p<0·0098), tuberculosis nucleic acid amplification tests (-19·2% [-32·7 to -3·1]; p=0·0241), and care by a tuberculosis specialist provider (-17·2% [-33·1 to -22·3]; p<0·0087). Longer delays were associated with an increased rate of respiratory complications even after controlling for patient characteristics, and an increased rate of secondary tuberculosis among dependents.

INTERPRETATION

In the USA, the median health-care delay for privately insured patients with tuberculosis exceeds WHO-recommended levels of 21 days (3 weeks). The results suggest the need for health-care provider education on best practices in tuberculosis diagnosis, including the use of molecular tests and the maintenance of a high index of suspicion for the disease.

FUNDING

US National Institutes of Health.

A Semi-Automated Approach for Multilingual Terminology Matching: Mapping the French Version of the ICD-10 to the ICD-10 CM

The aim of this study was to develop a simple method to map the French International Statistical Classification of Diseases and Related Health Problems, 10th revision (ICD-10) with the International Classification of Diseases, 10th Revision, Clinical Modification (ICD-10 CM). We sought to map these terminologies forward (ICD-10 to ICD-10 CM) and backward (ICD-10 CM to ICD-10) and to assess the accuracy of these two mappings. We used several terminology resources such as the Unified Medical Language System (UMLS) Metathesaurus, Bioportal, the latest version available of the French ICD-10 and several official mapping files between different versions of the ICD-10. We first retrieved existing partial mapping between the ICD-10 and the ICD-10 CM. Then, we automatically matched the ICD-10 with the ICD-10-CM, using our different reference mapping files. Finally, we used manual review and natural language processing (NLP) to match labels between the two terminologies. We assessed the accuracy of both methods with a manual review of a random dataset from the results files. The overall matching was between 94.2 and 100%. The backward mapping was better than the forward one, especially regarding exact matches. In both cases, the NLP step was highly accurate. When there are no available experts from the ontology or NLP fields for multi-lingual ontology matching, this simple approach enables secondary reuse of Electronic Health Records (EHR) and billing data for research purposes in an international context.

PR2ALIGN: a stand-alone software program and a web-server for protein sequence alignment using weighted biochemical properties of amino acids

Background

Alignment of amino acid sequences is the main sequence comparison method used in computational molecular biology. The selection of the amino acid substitution matrix best suitable for a given alignment problem is one of the most important decisions the user has to make. In a conventional amino acid substitution matrix all elements are fixed and their values cannot be easily adjusted. Moreover, most existing amino acid substitution matrices account for the average (dis)similarities between amino acid types and do not distinguish the contribution of a specific biochemical property to these (dis)similarities.

Findings

PR2ALIGN is a stand-alone software program and a web-server that provide the functionality for implementing flexible user-specified alignment scoring functions and aligning pairs of amino acid sequences based on the comparison of the profiles of biochemical properties of these sequences. Unlike the conventional sequence alignment methods that use 20x20 fixed amino acid substitution matrices, PR2ALIGN uses a set of weighted biochemical properties of amino acids to measure the distance between pairs of aligned residues and to find an optimal minimal distance global alignment. The user can provide any number of amino acid properties and specify a weight for each property. The higher the weight for a given property, the more this property affects the final alignment. We show that in many cases the approach implemented in PR2ALIGN produces better quality pair-wise alignments than the conventional matrix-based approach.

Conclusions

PR2ALIGN will be helpful for researchers who wish to align amino acid sequences by using flexible user-specified alignment scoring functions based on the biochemical properties of amino acids instead of the amino acid substitution matrix. To the best of the authors’ knowledge, there are no existing stand-alone software programs or web-servers analogous to PR2ALIGN. The software is freely available from http://pr2align.rit.albany.edu.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-015-1152-6) contains supplementary material, which is available to authorized users.

Spontaneous autoimmune gastritis and hypochlorhydria are manifest in the ileitis-prone SAMP1/YitFcs mice

SAMP1/YitFcs mice serve as a model of Crohn's disease, and we have used them to assess gastritis. Gastritis was compared in SAMP1/YitFcs, AKR, and C57BL/6 mice by histology, immunohistochemistry, and flow cytometry. Gastric acid secretion was measured in ligated stomachs, while anti-parietal cell antibodies were assayed by immunofluorescence and enzyme-linked immunosorbent spot assay. SAMP1/YitFcs mice display a corpus-dominant, chronic gastritis with multifocal aggregates of mononuclear cells consisting of T and B lymphocytes. Relatively few aggregates were observed elsewhere in the stomach. The infiltrates in the oxyntic mucosa were associated with the loss of parietal cell mass. AKR mice, the founder strain of the SAMP1/YitFcs, also have gastritis, although they do not develop ileitis. Genetic studies using SAMP1/YitFcs-C57BL/6 congenic mice showed that the genetic regions regulating ileitis had comparable effects on gastritis. The majority of the cells in the aggregates expressed the T cell marker CD3 or the B cell marker B220. Adoptive transfer of SAMP1/YitFcs CD4(+) T helper cells, with or without B cells, into immunodeficient recipients induced a pangastritis and duodenitis. SAMP1/YitFcs and AKR mice manifest hypochlorhydria and anti-parietal cell antibodies. These data suggest that common genetic factors controlling gastroenteric disease in SAMP1/YitFcs mice regulate distinct pathogenic mechanisms causing inflammation in separate sites within the digestive tract.

Altered autoimmune response in NOD-Alox15null mice (99.13)

12/15-lipoxygenase (12/15-LO) reacts with fatty acids to produce pro-inflammatory lipids, enhance IL-12 production by macrophages (MΦ), and its product 12-(S)-HETE induces pancreatic β-cell apoptosis at nM concentrations. Congenic NOD mice deficient in 12/15-LO (NOD-Alox15null) show a significant decrease in Type 1 diabetes (T1D) development (2.5 vs. &gt;60% in ♀ by 30 wks). We tested the effects of the deficiency on the immune system in NOD-Alox15null vs. NOD mice. Adoptive transfer of diabetic (diab) or non-diabetic (non-diab) NOD, and non-diab NOD-Alox15null splenocytes (cells) determined ability of T1D disease transfer in NOD.scids. Both diab and non-diab NOD cells conferred T1D in NOD.scid hosts, but non-diab NOD-Alox15null cells did not (&gt;8 wks post-transfer). NOD-Alox15null.scids were also injected with either NOD (diab and non-diab) or NOD-Alox15null (non-diab) cells. NOD cells still transferred disease, but NOD-Alox15null cells did not. As transferred splenocytes were mainly T and B cells, we tested for 12/15-LO mRNA expression in these subsets. 12/15-LO levels were minimally detectable, suggesting that immune effects are likely due to indirect effects on B and T cells. To study the mechanism, we looked at the role of 12/15-LO on APCs. Fewer MΦ infiltrate the pancreas of NOD-Alox15null mice at 4 wks of age compared to NOD controls. Also, MΦ from 10-wko NOD-Alox15null mice show reduced IL-12 expression compared to age-matched NODs. Therefore, 12/15-LO is a key regulator of the autoimmune response leading to T1D.

A web server for inferring the human N-acetyltransferase-2 (NAT2) enzymatic phenotype from NAT2 genotype

Summary:N-acetyltransferase-2 (NAT2) is an important enzyme that catalyzes the acetylation of aromatic and heterocyclic amine carcinogens. Individuals in human populations are divided into three NAT2 acetylator phenotypes: slow, rapid and intermediate. NAT2PRED is a web server that implements a supervised pattern recognition method to infer NAT2 phenotype from SNPs found in NAT2 gene positions 282, 341, 481, 590, 803 and 857. The web server can be used for a fast determination of NAT2 phenotypes in genetic screens.

Availability:Freely available at http://nat2pred.rit.albany.edu

Contact:ikuznetsov@albany.edu; rmoslehi@albany.edu

Supplementary information:Supplementary data are available at Bioinformatics online.

FlexPred: a web-server for predicting residue positions involved in conformational switches in proteins

Conformational switches observed in the protein backbone play a key role in a variety of fundamental biological activities. This paper describes a web-server that implements a pattern recognition algorithm trained on the examples from the Database of Macromolecular Movements to predict residue positions involved in conformational switches. Prediction can be performed at an adjustable false positive rate using a user-supplied protein sequence in FASTA format or a structure in a Protein Data Bank (PDB) file. If a protein sequence is submitted, then the web-server uses sequence-derived information only (such as evolutionary conservation of residue positions). If a PDB file is submitted, then the web-server uses sequence-derived information and residue solvent accessibility calculated from this file.

GM-CSF induces STAT5 binding at epigenetic regulatory sites within the Csf2 promoter of non-obese diabetic (NOD) mouse myeloid cells

Myeloid cells from non-obese diabetic (NOD) mouse and human type 1 diabetic (T1D) patients overexpress granulocyte-macrophage colony stimulation factor (GM-CSF). This overproduction prolongs the activation of signal transduction and activator of transcription 5 (STAT5) proteins, involved in GM-CSF-induced control of myeloid cell gene expression. We found that GM-CSF can regulate the binding of STAT5 on the promoter of its own gene, Csf2, within regions previously identified as sites of chromatin epigenetic modification important to the regulation of GM-CSF during myeloid differentiation and inflammation. We found multiple sequence polymorphisms within NOD mouse chromosome 11 Idd4.3 diabetes susceptibility region that alter STAT5 GAS binding sequences within the Csf2 promoter. STAT5 binding at these sites in vivo is increased significantly in GM-CSF-stimulated-bone marrow cells and in unactivated, high GM-CSF-producing macrophages from NOD mice as compared to non-autoimmune C57BL/6 mouse myeloid cells. Thus, GM-CSF overproduction by NOD myeloid cells may be perpetuating a positive epigenetic regulatory feedback on its own gene expression through its induction of STAT5 binding to its promoter. These findings suggest that aberrant STAT5 binding at epigenetic regulatory sites may contribute directly to immunopathology through cytokine-induced gene expression dysregulation that can derail myeloid differentiation and increase inflammatory responsiveness.

Smooth muscle of telokin-deficient mice exhibits increased sensitivity to Ca2+ and decreased cGMP-induced relaxation

Cyclic nucleotides can relax smooth muscle without a change in [Ca2+]i, a phenomenon termed Ca2+ desensitization, contributing to vasodilation, gastrointestinal motility, and airway resistance. The physiological importance of telokin, a 17-kDa smooth muscle-specific protein and target for cyclic nucleotide-induced Ca2+ desensitization, was determined in telokin null mice bred to a congenic background. Telokin null ileal smooth muscle homogenates compared to wild type exhibited an approximately 30% decrease in myosin light-chain phosphatase (MLCP) activity, which was reflected in a significant leftward shift (up to 2-fold at pCa 6.3) of the Ca2+ force relationship accompanied by an increase in myosin light-chain phosphorylation. No difference in the Ca2+ force relationship occurred in telokin WT and knockout (KO) aortas, presumably reflecting the normally approximately 5-fold lower telokin content in aorta vs. ileum smooth muscle. Ca2+ desensitization of contractile force by 8-Br-cGMP was attenuated by 50% in telokin KO intestinal smooth muscle. The rate of force relaxation reflecting MLCP activity, in the presence of 50 microM 8-Br-cGMP, was also significantly slowed in telokin KO vs. WT ileum and was rescued by recombinant telokin. Normal thick filaments in telokin KO smooth muscles indicate that telokin is not required for filament formation or stability. Results indicate that a primary role of telokin is to modulate force through increasing MLCP activity and that this effect is further potentiated through phosphorylation by cGMP in telokin-rich smooth tissues.

Defective T-cell activation is associated with augmented transforming growth factor Beta sensitivity in mice with mutations in the Sno gene

The proto-oncogene Sno has been shown to be a negative regulator of transforming growth factor beta (TGF-beta) signaling in vitro, using overexpression and artificial reporter systems. To examine Sno function in vivo, we made two targeted deletions at the Sno locus: a 5' deletion, with reduced Sno protein (hypomorph), and an exon 1 deletion removing half the protein coding sequence, in which Sno protein is undetectable in homozygotes (null). Homozygous Sno hypomorph and null mutant mice are viable without gross developmental defects. We found that Sno mRNA is constitutively expressed in normal thymocytes and splenic T cells, with increased expression 1 h following T-cell receptor ligation. Although thymocyte and splenic T-cell populations appeared normal in mutant mice, T-cell proliferation in response to activating stimuli was defective in both mutant strains. This defect could be reversed by incubation with either anti-TGF-beta antibodies or exogenous interleukin-2 (IL-2). Together, these findings suggest that Sno-dependent suppression of TGF-beta signaling is required for upregulation of growth factor production and normal T-cell proliferation following receptor ligation. Indeed, both IL-2 and IL-4 levels are reduced in response to anti-CD3 epsilon stimulation of mutant T cells, and transfected Sno activated an IL-2 reporter system in non-T cells. Mutant mouse embryo fibroblasts also exhibited a reduced cell proliferation rate that could be reversed by administration of anti-TGF-beta. Our data provide strong evidence that Sno is a significant negative regulator of antiproliferative TGF-beta signaling in both T cells and other cell types in vivo.

The anti-inflammatory compound lisofylline prevents Type I diabetes in non-obese diabetic mice

AIMS/HYPOTHESIS

Pro-inflammatory cytokines are increased during the active stages of Type I (insulin-dependent) diabetes mellitus. The aim of this study was to investigate the applicability of using a new anti-inflammatory compound, Lisofylline, to prevent diabetes in non-obese diabetic (NOD) mice. Lisofylline has previously been shown to block Th1 cell differentiation and to reduce IL-1 beta-induced dysfunction in rat islets.

METHODS

Lisofylline was added to isolated NOD islets in vitro, with or without IL-1 beta. Insulin secretion and DNA damage of the islets was assessed. Lisofylline was administered to female non-obese diabetic mice starting at 4, 7 and 17 weeks of age for 3 weeks. Cytokines and blood glucose concentrations were monitored. Histology and immunohistochemistry were carried out in pancreatic sections. Splenocytes isolated from donor mice were intravenously injected into immunodeficient NOD (NOD.scid) mice.

RESULTS

In vitro, Lisofylline preserved beta-cell insulin secretion and inhibited DNA damage of islets in the presence of IL-1 beta. In vivo, Lisofylline suppressed IFN-gamma production, reduced the onset of insulitis and diabetes, and inhibited diabetes after transfer of splenocytes from Lisofylline-treated donors to NOD.scid recipients. However, cotransfer of splenocytes from both Lisofylline-treated and diabetic NOD donors did not suppress diabetes in recipient mice.

CONCLUSION/INTERPRETATION

Lisofylline prevents the onset of autoimmune diabetes in NOD mice by a mechanism that does not seem to enhance the function of regulatory T cells, but could be associated with suppression of proinflammatory cytokines and reduction of cellular infiltration in islets. This study suggests that Lisofylline could have therapeutic benefits in preventing the onset of Type I diabetes.

NZM2328: a new mouse model of systemic lupus erythematosus with unique genetic susceptibility loci

Among NZB/W-derived New Zealand mixed (NZM) strains, only NZM/Aeg2410 (NZM2410) has been well characterized. In contrast to NZM2410, NZM2328 mice develop autoantibodies and acute and severe chronic glomerulonephritis (GN) with female predominance similarly to NZB/WF1 and humans with systemic lupus erythematosus (SLE). Chronic GN with glomerular sclerosis and tubular atrophy but not acute GN was correlated with severe proteinuria. In a backcross analysis of (NZM2328 X C57L/J) F1 X NZM2328, four SLE susceptibility genomic intervals were identified. One of them (Cgnz1) is on the telomeric end of chromosome 1 and close to Sle1. It was significantly linked to chronic GN. A locus (Agnz1) distinct from Cgnz1 on this interval was suggestively linked to acute GN. Two genetic intervals on chromosome 17 were also suggestively linked to acute GN, one of which is the H-2-Tnf complex, while the other (Agnz2) is on the distal end of the chromosome. A single locus (Adaz1) identified in the midregion of chromosome 4 in NZM2328 mice was suggestively linked to plasma levels of IgG anti-dsDNA autoantibodies. These results differ significantly from those in the backcross analysis of (NZM2410 X C57BL/6)F1 X NZM2410 by other investigators. They support the concept that different sets of genes are involved in acute and chronic GN. The genomic differences between the NZM strains and between C57L/J and C57BL/6 account for the differences between our analysis and that on NZM 2410. These results provide evidence for the importance of background genes on the expression of SLE, with implications for genetic studies of human SLE.

Derivation of diabetes-resistant congenic lines from the nonobese diabetic mouse

Autoimmune diabetes is a polygenic disease process in man and rodents. To identify and characterize genes involved in the pathogenesis of diabetes in nonobese diabetic (NOD) mice, we initiated a repetitive backcross of diabetes-resistant C57L/J mice onto the NOD strain. This breeding scheme was based on the premise that selection for the trait of disease resistance among genetically mixed mice could be used to maintain transmission of nonpermissive alleles from the diabetes-resistant strain at critical diabetes susceptibility loci. Each of the three recombinant congenic mouse lines derived by this strategy retains a unique constellation of C57L/J-derived DNA segments. Consistent with the involvement of different genetic loci, the pancreatic histology of disease-resistant mice differs from that in NOD mice in a line-specific manner. Functional studies using these lines demonstrate that pathogenesis of autoimmune diabetes is a multistep process which can be blocked at a minimum of three critical, genetically determined points.

Genetics of autoimmune diabetes in animal models

Type I diabetes has resisted direct genetic analysis in humans but two excellent models of disease in rodents provide a more readily manipulated alternative for study. These rodent models are being used successfully to localize the genes that are involved in disease pathogenesis in preparation for positional cloning. In addition, mice carrying transgenes and null mutations related to T cell function have been used to demonstrate potential mechanisms for both MHC-dependence and specific effector functions, such as cytokine release and cytotoxicity.

A diabetes-associated T-cell autoantigen maps to a telomeric locus on mouse chromosome 6

Identification of diabetes-associated T-cell autoantigens is important for understanding the immunopathology of diabetes and developing improved therapeutic strategies. We have used a genetic approach to move toward identifying the autoantigen recognized by a diabetogenic islet-specific T-cell clone from a nonobese diabetic (NOD) mouse. The unique antigen recognition pattern of this clone was utilized to map the gene encoding the antigen (or its expression) by genetic linkage analysis. In vitro analysis of T-cell proliferation by this clone showed that the capacity of the islets to stimulate T cells segregates as a single codominant gene in BALB/cByJ x (BALB/cByJ x NOD/Bdc) backcross mice. This phenotype was tightly linked to two microsatellites in the telomeric region of mouse chromosome 6.

Islet-specific T cell clones transfer diabetes to nonobese diabetic (NOD) F1 mice

To investigate diabetes resistance to T cell-mediated disease transfer, we administered islet-specific T cell clones to the F1 progeny of nonobese diabetic (NOD) mice that were crossed with various nondiabetes-prone inbred mouse strains. We investigated four diabetogenic CD4+ T cell clones and all induced insulitis and full development of diabetes in (SWR x NOD)F1, (SJL x NOD)F1, and (C57BL/6 x NOD)F1 mice. In contrast, (BALB/c x NOD)F1 and (CBA x NOD)F1 mice were susceptible to disease transfer by some T cell clones but not others, and (C57/L x NOD)F1 mice seemed to be resistant to both insulitis and disease transfer by all of the clones tested. Disease induced by the T cell clones in susceptible F1 strains was age dependent and could only be observed in recipients younger than 13 days old. Full or partial disease resistance did not correlate with the presence or absence of I-E, different levels of Ag expression in islet cells, or differences in APC function. The results from this study suggest that there may be multiple factors contributing to susceptibility of F1 mice to T cell clone-mediated induction of diabetes, including non-MHC-related genetic background, the immunologic maturity of the recipient, and individual characteristics of the T cell clones.

Islet-specific T cell clones transfer diabetes to nonobese diabetic (NOD) F1 mice

To investigate diabetes resistance to T cell-mediated disease transfer, we administered islet-specific T cell clones to the F1 progeny of nonobese diabetic (NOD) mice that were crossed with various nondiabetes-prone inbred mouse strains. We investigated four diabetogenic CD4+ T cell clones and all induced insulitis and full development of diabetes in (SWR x NOD)F1, (SJL x NOD)F1, and (C57BL/6 x NOD)F1 mice. In contrast, (BALB/c x NOD)F1 and (CBA x NOD)F1 mice were susceptible to disease transfer by some T cell clones but not others, and (C57/L x NOD)F1 mice seemed to be resistant to both insulitis and disease transfer by all of the clones tested. Disease induced by the T cell clones in susceptible F1 strains was age dependent and could only be observed in recipients younger than 13 days old. Full or partial disease resistance did not correlate with the presence or absence of I-E, different levels of Ag expression in islet cells, or differences in APC function. The results from this study suggest that there may be multiple factors contributing to susceptibility of F1 mice to T cell clone-mediated induction of diabetes, including non-MHC-related genetic background, the immunologic maturity of the recipient, and individual characteristics of the T cell clones.

The accessory molecule Lgp55 plays a role early in murine fetal thymocyte differentiation

A rat IgM monoclonal antibody, PA3-795, inhibits the antigen-specific responses of mouse T-cell hybridomas. It recognizes a heavily glycosylated cell-surface protein, designated Lgp55, that is detectable after activation on mature T cells. During fetal life, Lgp55 is found at high levels on newly immigrant thymic T-cell precursors prior to surface expression of other T-lineage molecules. High levels of expression are also found on thymocytes in the outer cortex of adult mice. Thymocytes at later stages of differentiation bear decreasing amounts of surface Lgp55, and none is detectable on "single-positive" thymocytes in the thymic medulla or on resting mature T cells from the periphery. Addition of monoclonal anti-Lgp55 to fetal thymus organ culture decreases the output of "mature" CD4 single-positive thymocytes when it is begun before fetal day 13.5. These findings suggest that Lgp55 contributes to cell-cell interactions that regulate very early steps in T-cell development in the mouse.

Superantigen-like effects and incidence of diabetes in NOD mice

The population of T-cells that develops in any individual can be divided into families based on sequence differences in the beta-chain variable region of the T-cell receptor heterodimer. Major histocompatibility complex products and endogenous retroviral gene products have both been shown to exert powerful influences on the frequency distribution of T-cell receptor beta-chain variable region families in the mouse. In most mouse strains, these repertoire modifiers appear to be fully functional early in mouse development and shape a repertoire of antigen specificities that remains essentially unchanged from the first weeks of life until old age. In NOD mice, an inbred mouse model of type I diabetes, puberty in males coincides with a beta-chain variable region-specific T-cell expansion that mimics the results of exposure to exogenous superantigens in immunologically mature animals. The subsequent behavior of this subset indicates that it may play a role in the relative protection of male NOD mice from complete pancreatic beta-cell destruction and overt diabetes.

T-cell repopulation following neonatal injection of non-obese diabetic (NOD) mice with anti-T-cell antibodies

Non-obese diabetic (NOD) mice injected with CD3 antibody as newborns have a reduced incidence of diabetes, raising the possibility that the neonatal injection caused a long-lasting change in circulating T cells. The present study shows that NOD and BALB/c mice injected with soluble CD3 antibody in the first 2 days of life sustained an 80-95% reduction in the number of circulating T cells lasting for 2-3 weeks, with T cells returning after 4 weeks, and reaching control values after 6 weeks. The T cells which appeared in intact mice 4-6 weeks after injection showed no excess of T-cell receptor (TcR) delta expressing cells. They had a similar distribution into CD4 and CD8 subsets as uninjected controls, and a similar usage and cell surface expression of four T-cell receptor V beta families. Labelled CD3 antibody was detected in the serum for up to 2 weeks after injection into neonates and was enriched in the thymus. Adoptively transferred T cells continued to be cleared from the circulation for 4 weeks following antibody injection. The properties of T cells which had been exposed to CD3 neonatally were investigated in animals who were first injected with CD3 antibody and then thymectomized. These animals had reduced numbers of T cells at 12 weeks of age. The surviving T cells showed a Ca2+ flux when stimulated but their proliferation in response to concanavalin A (Con A) was reduced, even in the presence of irradiated accessory cells or T-cell supernatant co-stimulator factors. Although the representation of four different V beta families was the same as in the uninjected controls, the density of expression of the T-cell receptor was reduced. The data indicate that the limited number of T cells which survive the injection are functionally deficient and that an intact thymus is required for full T-cell repopulation following neonatal CD3 injection into NOD mice.

I-E-independent deletion of V beta 17a+ T cells by Mtv-3 from the nonobese diabetic mouse

Analysis of TCR beta-chain V region (V beta) frequency among NOD lymphocytes reveals a profound depletion of V beta 3+ T cells, and a recent study has linked this phenomenon to the Mtv-3 insertion on chromosome 11. When the V beta 17a gene segment is introduced into mice with an nonobese diabetic mouse background, T cells bearing the TCR encoded by this gene segment are also dramatically reduced in frequency. Deletion of V beta 17a+ T cells segregates with deletion of T cells bearing V beta 3 and occurs in the absence of I-E, which had been shown in previous studies to be a major deleting element for V beta 17a+ thymocytes.

I-E-independent deletion of V beta 17a+ T cells by Mtv-3 from the nonobese diabetic mouse

Analysis of TCR beta-chain V region (V beta) frequency among NOD lymphocytes reveals a profound depletion of V beta 3+ T cells, and a recent study has linked this phenomenon to the Mtv-3 insertion on chromosome 11. When the V beta 17a gene segment is introduced into mice with an nonobese diabetic mouse background, T cells bearing the TCR encoded by this gene segment are also dramatically reduced in frequency. Deletion of V beta 17a+ T cells segregates with deletion of T cells bearing V beta 3 and occurs in the absence of I-E, which had been shown in previous studies to be a major deleting element for V beta 17a+ thymocytes.

Diabetes in NOD mice does not require T lymphocytes expressing V beta 8 or V beta 5

The incidence of destructive pancreatic infiltrates and overt diabetes in animal models of insulin-dependent (type I) diabetes mellitus can be greatly reduced by inactivating or eliminating most T lymphocytes early in life. Because of theoretical and practical concerns about inducing long-term pan-T-lymphocyte inactivation for prevention or treatment of type I diabetes in humans, we hoped that more selective suppression of only the diabetogenic T lymphocyte population might be possible. To this end, two groups suggested that diabetogenic subpopulations of T lymphocytes in NOD mice could be identified by the protein sequence of their T-lymphocyte receptors. This assertion was based on experimental elimination of candidate T-lymphocyte subpopulations in two different short-term models of diabetes induction in NOD mice. For these experiments, identification and elimination of T-lymphocyte subsets were accomplished with monoclonal antibodies that bind specifically to the variable region of the beta-chain (V beta) of the T-lymphocyte antigen receptor and divide the T-lymphocyte pool of the NOD mouse into approximately 20 V beta subsets. To test the relationship between the two T-lymphocyte V beta subsets implicated in these studies and pancreatic beta-cell destruction in unmanipulated animals, both T-lymphocyte subpopulations identified were genetically eliminated from NOD-derived mice by introduction of a mutant T-lymphocyte receptor V beta gene, from which these sequences are genomically deleted. Histological evidence of severe beta-cell destruction and overt diabetes was found in mice homozygous for the deleted V beta gene, indicating that neither V beta gene segment identified in previous studies is required for diabetogenesis in unmanipulated diabetes-prone mice.

Acceleration of diabetes in young NOD mice with a CD4+ islet-specific T cell clone

Nonobese diabetic (NOD) mice develop an autoimmune form of diabetes, becoming hyperglycemic after 3 months of age. This process was accelerated by injecting young NOD mice with CD4+ islet-specific T cell clones derived from NOD mice. Overt diabetes developed in 10 of 19 experimental animals by 7 weeks of age, with the remaining mice showing marked signs of the disease in progress. Control mice did not become diabetic and had no significant pancreatic infiltration. This work demonstrates that a CD4 T cell clone is sufficient to initiate the disease process in the diabetes-prone NOD mouse.

A trial of nicotinamide in newly diagnosed patients with type 1 (insulin-dependent) diabetes mellitus

Various agents have been tried in subjects with newly diagnosed Type 1 (insulin-dependent) diabetes mellitus in an attempt to preserve Beta-cell function. In this double-blind study, nicotinamide or placebo were given for one year to 35 children and adolescents with newly-diagnosed Type 1 diabetes. All subjects were within six weeks of diagnosis and were between the ages of 6 and 18 years. Nicotinamide, a poly-(ADP-ribose) synthetase inhibitor, was given in a dose of 100 mg/year of age up to a maximum of 1.5 g/day. There were no initial differences between the 17 control and the 18 test subjects in relation to mean age, sex distribution, or severity at onset. Mean insulin dosages and HbA1 values were similar for the two groups during the year of study. Fasting and glucagon-stimulated C-peptide levels were similar for the control and nicotinamide treated groups at the beginning and after 4 and 12 months. There were no differences in remission rates between the two groups. Nicotinamide, at this dosage, does not preserve residual insulin secretion in subjects with newly diagnosed Type 1 diabetes.

Identification of a new cell surface glycoprotein with accessory function in murine T cell responses

T cell binding to target cells involves not only the TCR and its MHC-bound ligand, but also a collection of additional proteins on both the T cell and its target. In an attempt to identify new molecules involved in this binding, mAb were raised against APC, and screened for their abilities to inhibit T cell recognition of Ag plus MHC on B cells. Six antibodies were identified that inhibited this reaction and that bound a cell-surface glycoprotein (Lgp55), with core polypeptide Mr 30,000 and a glycosylated Mr of approximately 55,000 depending upon the cell source. The properties of Lgp55 were consistent with it being the mouse homologue of a recently identified human ligand (intercellular adhesion molecule-2) for lymphocyte functional Ag-1 because the proteins are of comparable Mr, and antibody to Lgp55, like anti-lymphocyte functional antigen-1, blocks T cell recognition of Ag presented by B cells, but not of Ag presented by mouse fibroblasts.

Identification of a new cell surface glycoprotein with accessory function in murine T cell responses

T cell binding to target cells involves not only the TCR and its MHC-bound ligand, but also a collection of additional proteins on both the T cell and its target. In an attempt to identify new molecules involved in this binding, mAb were raised against APC, and screened for their abilities to inhibit T cell recognition of Ag plus MHC on B cells. Six antibodies were identified that inhibited this reaction and that bound a cell-surface glycoprotein (Lgp55), with core polypeptide Mr 30,000 and a glycosylated Mr of approximately 55,000 depending upon the cell source. The properties of Lgp55 were consistent with it being the mouse homologue of a recently identified human ligand (intercellular adhesion molecule-2) for lymphocyte functional Ag-1 because the proteins are of comparable Mr, and antibody to Lgp55, like anti-lymphocyte functional antigen-1, blocks T cell recognition of Ag presented by B cells, but not of Ag presented by mouse fibroblasts.

Involvement of major histocompatibility complex products in tolerance induction in the thymus

KJ23a+ T cell clones, which bear the determinant encoded by the V beta 17a T cell receptor gene segment, frequently recognize IE molecules of various murine H-2 haplotypes. In the presence of IE molecules, thymic maturation of KJ23a+ clones is infrequent. We investigated the basis of this phenomenon by blocking expression of IE molecules with monoclonal anti-IE antibodies in organ cultures of fetal thymus and in neonates from the C57BR/cdJ strain (H-2k, V beta 17a homozygous). Our data support the contention that this process results from deletion of clones with anti-IE reactivity, as functional blocking of the IE molecule results in maturation of IE-reactive clones and increased numbers of KJ23a+ mature cells. In addition, we noted that blocking of functional IE expression in this haplotype permitted development of both CD4+/KJ23a+ and CD8+/KJ23a+ T cells. The CD4+ clones isolated from anti-IE-treated animals were frequently reactive against IEk; we could demonstrate no alloreactivity against B cell or B lymphoma stimulators in the CD4- clones. We conclude that clonal deletion events during thymic development may be initiated by T cell precursor interactions with MHC molecules against which the mature clones display no measurable reactivity. Specifically, clones destined to be MHC Class I-reactive may be deleted during development by interactions with MHC Class II molecules.

Involvement of major histocompatibility complex products in tolerance induction in the thymus

KJ23a+ T cell clones, which bear the determinant encoded by the V beta 17a T cell receptor gene segment, frequently recognize IE molecules of various murine H-2 haplotypes. In the presence of IE molecules, thymic maturation of KJ23a+ clones is infrequent. We investigated the basis of this phenomenon by blocking expression of IE molecules with monoclonal anti-IE antibodies in organ cultures of fetal thymus and in neonates from the C57BR/cdJ strain (H-2k, V beta 17a homozygous). Our data support the contention that this process results from deletion of clones with anti-IE reactivity, as functional blocking of the IE molecule results in maturation of IE-reactive clones and increased numbers of KJ23a+ mature cells. In addition, we noted that blocking of functional IE expression in this haplotype permitted development of both CD4+/KJ23a+ and CD8+/KJ23a+ T cells. The CD4+ clones isolated from anti-IE-treated animals were frequently reactive against IEk; we could demonstrate no alloreactivity against B cell or B lymphoma stimulators in the CD4- clones. We conclude that clonal deletion events during thymic development may be initiated by T cell precursor interactions with MHC molecules against which the mature clones display no measurable reactivity. Specifically, clones destined to be MHC Class I-reactive may be deleted during development by interactions with MHC Class II molecules.

Effect of cyclosporine on immunologically mediated diabetes in nonobese diabetic mice

Spontaneous diabetes in NOD mice has an immunologically mediated cause and is a T cell-dependent process. When diabetic NOD mice are grafted with cultured BALB/c islet tissue, the islet graft is destroyed by disease recurrence in the graft. Disease recurrence is a CD4 T cell-dependent process as determined by in vivo administration of anti-CD4 or anti-CD8 monoclonal antibody prior to the grafting of islet tissue. Cyclosporine functions in the early sequence of T cell activation by regulating the production of messenger RNA for lymphokines synthesis. Cyclosporine does not inhibit the synthesis of lymphokine once the lymphokine message is present in the cell. Thus, we might expect cyclosporine to be relatively inefficient as an agent for the regulation of disease recurrence following transplantation to actively diabetic recipients, and we would expect cyclosporine to be more effective when administered before the onset of the disease. Low-dose cyclosporine treatment can prevent development of the disease when the drug is administered before the onset of disease. Data presented here show that cyclosporine is ineffective in controlling disease recurrence in the islet graft transplanted to actively diabetic animals. Also, when we eliminate CD4 T cells from the diseased animals and graft islet tissue prior to the administration of cyclosporine, we are unable to maintain a graft with low-dose cyclosporine therapy. This result leads us to conclude that, although anti-CD4 treatment controls the expression of the disease process and allows the survival and function of the islet graft, this treatment does not return diseased animals to the prediabetic condition in which the development of diabetes can be controlled by low-dose cyclosporine therapy.

The development of helper T cell precursors in mouse thymus

We have examined the appearance in mouse ontogeny of thymocyte precursors for Ag-specific, MHC-restricted Th. These cells are first detectable at day 18 of fetal life, about 1 day after alpha/beta, TCR-positive cells begin to appear. These early Th precursors are not dependent on the thymus for priming with Ag and MHC, and are L3T4+, Lyt-2-. Thus, these cells already have the phenotype of mature Th. In neonatal F1 animals expressing both IAk and IAb, the appearance of Th precursors restricted by either IAk or IAb is specifically inhibited by treatment of the mice with anti-IAk or anti-IAb antibodies, respectively. These results indicate that cells of mature T cell phenotype and function can arise fairly rapidly from immature, receptor-bearing precursors, once these appear. Moreover the results are in line with those previously obtained in chimeric animal experiments which suggested that specific interaction of TCR on thymocytes with class II alleles in the thymus is required for the subsequent appearance of T cells restricted by those class II alleles.

Both immature and mature T cells mobilize Ca2+ in response to antigen receptor crosslinking

T cells develop from prothymocytes which express no detectable antigen receptors to immature thymocytes with few receptors, eventually becoming mature thymocytes and peripheral T cells with 20,000-40,000 receptors per cell. Recent studies suggest that immature thymocytes are immunologically unresponsive. We have suggested that an early step in signal transduction following engagement of the T cell receptor might differ in immature and mature T cells. Here we examine anti-receptor antibody mediated induction of calcium mobilization in immature and mature T cells. Results indicate that antigen receptors on both immature and mature receptor-positive T cells transduce signals via calcium mobilization. Significant differences were observed, however, between these populations in the magnitude of influx of extracellular Ca2+ following binding of antireceptor antibody. Specifically immature cells show a much reduced Ca2+ influx response compared to mature cells which could result from a low Ca2+ channel frequency in the plasma membranes of immature T cells, or from less efficient activation of existing channels.

Expression and role of the T cell receptor in early thymocyte differentiation in vitro

Fetal thymus organ culture was used to study the expression and function of antigen-specific, major histocompatibility complex-restricted receptors on thymocytes. Receptor gene rearrangement and expression occurred de novo in organ culture indicating that these events are induced in the thymus itself, presumably in response to thymus-derived stimuli. During organ culture a population of immature thymocytes expressing low levels of receptors developed first, and then diminished as mature thymocytes with high levels of receptor expression appeared. Continuous culture with antireceptor antibody modulated receptor from the surfaces of immature thymocytes, but did not prevent their appearance or accumulation. By contrast, appearance of receptor-bearing mature thymocytes was prevented in the presence of antireceptor antibody. These results indicate that the receptor is not essential for the generation of immature thymocytes but is involved in the selection or maintenance of mature cells from this pool.

Expression and role of the T cell receptor in early thymocyte differentiation in vitro

Fetal thymus organ culture was used to study the expression and function of antigen-specific, major histocompatibility complex-restricted receptors on thymocytes. Receptor gene rearrangement and expression occurred de novo in organ culture indicating that these events are induced in the thymus itself, presumably in response to thymus-derived stimuli. During organ culture a population of immature thymocytes expressing low levels of receptors developed first, and then diminished as mature thymocytes with high levels of receptor expression appeared. Continuous culture with antireceptor antibody modulated receptor from the surfaces of immature thymocytes, but did not prevent their appearance or accumulation. By contrast, appearance of receptor-bearing mature thymocytes was prevented in the presence of antireceptor antibody. These results indicate that the receptor is not essential for the generation of immature thymocytes but is involved in the selection or maintenance of mature cells from this pool.

The role of the T-cell receptor in thymocyte maturation: effects in vivo of anti-receptor antibody

The T-cell receptor, which recognizes antigen plus a product of the major histocompatibility complex, has been postulated to drive T-cell maturation in the thymus by engaging major histocompatibility complex proteins expressed on thymic stromal cells. We tested this idea by injecting neonatal animals with an anti-receptor antibody, KJ16, that binds to about 20% of T cells and is capable of blocking receptor function. In the presence of this antibody, mature T cells bearing the KJ16 epitope failed to develop. On the other hand, although the antibody could be shown to bind to receptors on cortical thymocytes, it did not prevent the rapid expansion or survival of the bulk of the KJ16+ cells in this population. These results are consistent with the hypothesis that most cortical thymocytes arise by a receptor-independent mechanism and that only a small proportion of these cells mature by a process dependent on receptor-major histocompatibility complex interactions.