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Environmental and genetic factors define the susceptibility of an individual to autoimmune disease. Although common genetic pathways affect general immunological tolerance mechanisms in autoimmunity, the effects of such genes could vary under distinct immune challenges within different tissues. In this study, we demonstrate this by observing that autoimmune type 1 diabetes-protective haplotypes at the insulin-dependent diabetes susceptibility region 10 (Idd10) introgressed from chromosome 3 of C57BL/6 (B6) and A/J mice onto the NOD background increase the severity of autoimmune primary biliary cirrhosis induced by infection with Novosphingobium aromaticivorans, a ubiquitous alphaproteobacterium, when compared with mice having the NOD and NOD.CAST Idd10 type 1 diabetes-susceptible haplotypes. Substantially increased liver pathology in mice having the B6 and A/J Idd10 haplotypes correlates with reduced expression of CD101 on dendritic cells, macrophages, and granulocytes following infection, delayed clearance of N. aromaticivorans, and the promotion of overzealous IFN-γ– and IL-17–dominated T cell responses essential for the adoptive transfer of liver lesions. CD101-knockout mice generated on the B6 background also exhibit substantially more severe N. aromaticivorans-induced liver disease correlating with increased IFN-γ and IL-17 responses compared with wild-type mice. These data strongly support the hypothesis that allelic variation of the Cd101 gene, located in the Idd10 region, alters the severity of liver autoimmunity induced by N. aromaticivorans.

We have previously proposed that sequence variation of the CD101 gene between NOD and C57BL/6 mice accounts for the protection from type 1 diabetes (T1D) provided by the insulin-dependent diabetes susceptibility region 10 (Idd10), a

We have used the public sequencing and annotation of the mouse genome to delimit the previously resolved type 1 diabetes (T1D) insulin-dependent diabetes (Idd)18 interval to a region on chromosome 3 that includes the immunologically relevant candidate gene, Vav3. To test the candidacy of Vav3, we developed a novel congenic strain that enabled the resolution of Idd18 to a 604-kb interval, designated Idd18.1, which contains only two annotated genes: the complete sequence of Vav3 and the last exon of the gene encoding NETRIN G1, Ntng1. Targeted sequencing of Idd18.1 in the NOD mouse strain revealed that allelic variation between NOD and C57BL/6J (B6) occurs in noncoding regions with 138 single nucleotide polymorphisms concentrated in the introns between exons 20 and 27 and immediately after the 3′ untranslated region. We observed differential expression of VAV3 RNA transcripts in thymocytes when comparing congenic mouse strains with B6 or NOD alleles at Idd18.1. The T1D protection associated with B6 alleles of Idd18.1/Vav3 requires the presence of B6 protective alleles at Idd3, which are correlated with increased IL-2 production and regulatory T cell function. In the absence of B6 protective alleles at Idd3, we detected a second T1D protective B6 locus, Idd18.3, which is closely linked to, but distinct from, Idd18.1. Therefore, genetic mapping, sequencing, and gene expression evidence indicate that alteration of VAV3 expression is an etiological factor in the development of autoimmune β-cell destruction in NOD mice. This study also demonstrates that a congenic strain mapping approach can isolate closely linked susceptibility genes.

The understanding of the genetic basis of type 1 diabetes and other autoimmune diseases and the application of that knowledge to their treatment, cure and eventual prevention has been a difficult goal to reach. Cumulative progress in both mouse and human are finally giving way to some successes and significant insights have been made in the last few years. Investigators have identified key immune tolerance-associated phenotypes in convincingly reliable ways that are regulated by specific diabetes-associated chromosomal intervals. The combination of positional genetics and functional studies is a powerful approach to the identification of downstream molecular events that are causal in disease aetiology. In the case of type 1 diabetes, the availability of several animal models, especially the NOD mouse, has complemented the efforts to localize human genes causing diabetes and has shown that some of the same genes and pathways are associated with autoimmunity in both species. There is also growing evidence that the initiation or progression of many autoimmune diseases is likely to be influenced by some of the same genes.

The identification of causative genes for the autoimmune disease type 1 diabetes (T1D) in humans and candidate genes in the NOD mouse has made significant progress in recent years. In addition to sharing structural aspects of the MHC class II molecules that confer susceptibility or resistance to T1D, genes and pathways contributing to autoimmune pathogenesis are held in common by the two species. There are data demonstrating a similar need to establish central tolerance to insulin. Gene variants for the interacting molecules IL2 and CD25, members of a pathway that is essential for immune homeostasis, are present in mice and humans, respectively. Variation of two molecules that negatively regulate T cells, CTLA-4 and the tyrosine phosphatase LYP/PEP, are associated with susceptibility to human and NOD T1D. These observations underscore the value of the NOD mouse model for mechanistic studies on human T1D-associated molecular and cellular pathways.

One strategy to help identify susceptibility genes for complex, multifactorial diseases is to map disease loci in a representative animal model of the disorder. The nonobese diabetic (NOD) mouse is a model for human type 1 diabetes. Linkage and congenic strain analyses have identified several NOD mouse Idd (insulin dependent diabetes) loci, which have been mapped to small chromosome intervals, for which the orthologous regions in the human genome can be identified. Here, we have conducted re-sequencing and association analysis of six orthologous genes identified in NOD Idd loci: NRAMP1/SLC11A1 (orthologous to Nramp1/Slc11a1 in Idd5.2), FRAP1 (orthologous to Frap1 in Idd9.2), 4-1BB/CD137/TNFRSF9 (orthologous to 4-1bb/Cd137/Tnrfrsf9 in Idd9.3), CD101/IGSF2 (orthologous to Cd101/Igsf2 in Idd10), B2M (orthologous to B2m in Idd13) and VAV3 (orthologous to Vav3 in Idd18). Re-sequencing of a total of 110 kb of DNA from 32 or 96 type 1 diabetes cases yielded 220 single nucleotide polymorphisms (SNPs). Sixty-five SNPs, including 54 informative tag SNPs, and a microsatellite were selected and genotyped in up to 1,632 type 1 diabetes families and 1,709 cases and 1,829 controls. None of the candidate regions showed evidence of association with type 1 diabetes (P values > 0.2), indicating that common variation in these key candidate genes does not play a major role in type 1 diabetes susceptibility in the European ancestry populations studied.

The glycolytic enzyme phosphoglycerate mutase exists in two evolutionarily unrelated forms. Vertebrates have only the 2,3-bisphosphoglycerate-dependent enzyme (dPGM), whilst higher plants have only the cofactor-independent enzyme (iPGM). Certain eubacteria possess genes encoding both enzymes, and their respective metabolic roles and activities are unclear. We have over-expressed, purified and characterised the two PGMs of Escherichia coli. Both are expressed at high levels, but dPGM has a 10-fold higher specific activity than iPGM. Differential inhibition by vanadate was observed. The presence of an integral manganese ion in iPGM was confirmed by EPR spectroscopy.

Recommendations on limitation of summer sunlight exposure to prevent skin cancer may conflict with requirements to protect bone health through adequate vitamin D levels, the principal source being UVB in summer sunlight. We determined whether sufficient (> or =20 ng ml(-1)) and proposed optimal (> or =32 ng ml(-1)) 25(OH)D levels are attained by following UK guidance advising casual short exposures to UVB in summer sunlight, and performed the study under known conditions to enhance the specificity of future recommendations. During wintertime, when ambient UVB is negligible, 120 white Caucasians, aged 20-60 years, from Greater Manchester, UK (53.5 degrees N) received a simulated summer's sunlight exposures, specifically 1.3 standard erythemal dose, three times weekly for 6 weeks, while wearing T-shirt and shorts. The baseline winter data predict that 5% (confidence interval (CI): 2.7-8.6) of Greater Manchester white Caucasians have deficient (