Browsing by Subject "Antibodies, Antinuclear"
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
Item Antinuclear and anticytoplasmic antibodies: concepts and misconceptions(1984-07-12) Sontheimer, Richard D.Item Common Alleles of the SLAM/CD2 Family are Associated with Murine Lupus(2005-04-25) Limaye, Nisha; Wakeland, Edward K.The Sle1b locus on telomeric mouse chromosome 1 mediates a break in tolerance to chromatin in the NZM2410 model of the autoimmune disease Systemic Lupus Erythematosus (SLE). B6.Sle1b congenic mice produce anti-nuclear autoantibodies (ANAs), and have elevated activated B and CD4+ T cells, and mild splenomegaly. Fine mapping of Sle1b positioned it within a ~900 kb region between 171.3 and 172.2 Mb. A contig of 100 B6-derived Bacterial Artificial Chromosomes (BACs) was constructed across Sle1b, and sequencing of six BACs that form an overlapping tiling path across it revealed that the interval contains 24 genes, 19 of which are expressed in the spleen, and 14 of which are in B and CD4+ T cells. We carried out extensive candidate gene analyses on the spleen-expressed genes, including sequencing of all the exons and flanking introns in the lupus-resistant B6 and susceptible B6.Sle1b parental strains, as well as Quantitative Real-time PCR on B and CD4+ T cell cDNA to detect any potentially functional polymorphisms between them. These analyses showed that the SLAM/CD2 family of seven immunoregulatory receptors, clustered within the locus, are by far the best candidates to be the Sle1b gene(s). The members of this family play important roles in intercellular interactions, activation, and function, by engaging in homophilic interactions with themselves or with each other, on a wide variety of immune cell types. Sequence analyses of their extracellular ligand-binding immunoglobulin (Ig) domains revealed that the cluster forms two stable, linked haplotypes of alleles in 33 common inbred laboratory strains of mice. The B6-like haplotype is found only in a small set of C57-strains, while the B6.Sle1b-like haplotype is found in all of the remaining, including the autoimmune-prone MRL, NOD, and NZB, as well as non-autoimmune strains like 129, Balb/c, and C3H. Introgression of this common haplotype from 129 onto B6 also potentiates autoimmunity, causing phenotypes similar to those of B6.Sle1b mice, which derive this interval from the NZW parent of NZM2410. Autoimmunity is mediated, not by a rare mutation peculiar to the region from NZW, but instead by common polymorphic variants of this family, in combination with the downstream signaling and effector molecules and pathways present in the B6 genetic background, underlining the importance of epistasis in such complex, multigenic autoimmune phenotypes. An examination of the SLAM/CD2 Ig domains in a large group of wild-outbred and wild-derived inbred strains belonging to different species of Mus, and sub-species of Mus musculus, has shown that the "disease" alleles of this family are also very common in these populations, demonstrating that their prevalence in the lab strains is not simply an artifact of their inbreeding. The genes also show the presence of ancestral or trans-species polymorphisms, indicative of maintenance of these alleles by balancing selection, although we do not yet know what precisely drives it. The small size of the Sle1b susceptibility interval, and the presence of this linked cluster of attractive candidate genes within it, makes it hard to identify which gene or combination of genes within this family is actually responsible for the autoimmunity by any further recombinational analysis. We have instead turned to a BAC-transgenic rescue strategy by which to localize the gene to a single B6-derived BAC, by its ability to complement the ANA-production phenotype and rescue autoimmunity in B6.Sle1b mice. We believe the strategy is feasible because Sle1b has a strong allele dose effect, so that the presence of a B6 allele of the Sle1b gene causes a large drop in penetrance of ANA-production, from about 90% in nine month old B6.Sle1b females, to about 33% in (B6 X B6.Sle1b) F1s. Our data show that none of the non-SLAM/CD2 candidates within the region is able to rescue B6.Sle1b mice, despite being demonstrably expressed from their BAC-transgenes. BACs carrying certain SLItem In Vivo Identification of SLE1B: LY108 Mediates Autoantibody Production(2008-05-12) Chan, Alice; Wakeland, Edward K.In the NZM2410 model of murine lupus, Sle1b mediates anti-nuclear autoantibody (ANA) production. Our goal is to determine the causative gene in the Sle1b locus. Seven members of the SLAM/CD2 family are located within the Sle1b interval, and previous work has shown that structural and expression polymorphisms in lymphocytes distinguish two major SLAM/CD2 haplotypes. To further narrow the interval, we utilized a BAC transgenic rescue approach whereby BACs carrying the lupus-resistant B6 alleles were bred to B6.Sle1b mice to identify the region mediating ANA suppression. One BAC carrying Cd84 and Ly108 suppressed autoantibody production. We then generated BAC transgenic mice carrying the lupus-susceptible (129) and lupus-resistant (B6) alleles of Ly108 on the B6 and B6.Sle1b genetic background, respectively. The B6 allele of Ly108 suppresses ANA production on the lupus-susceptible B6.Sle1b background while the 129 allele induces ANA on the lupus-resistant B6 genome. Taken together, these data identify Ly108 as a causative gene in Sle1b. While Ly108 is needed to mediate the breach in tolerance, we have also identified other SLAM family members as genetic modifiers necessary to recapitulate fully penetrant, high titer ANA production as seen in Sle1b. We found that in vitro stimulation of B6.Sle1b CD4 T cells led to altered cytokine production, such as decreased IL4 production. Interestingly, these phenotypes have also been reported in knockouts of SLAM/CD2 family members as well as in the absence of the SLAM family adaptor, SAP. Our data indicates that the presence of the Sle1b haplotype, derived from either NZM2410 or 129, recapitulates these phenotypes, independent of the absence of these molecules. While recent reports have suggested a role for SAP in ANA development, we find that the breach in tolerance in Sle1b mice is SAP-independent. However, SAP is necessary to potentiate the autoantibody production. ANAs is an important biomarker for autoimmune diseases including, Systemic Lupus Erythematosus (SLE), and potentially identifies an autoimmune-prone state. We have identified genes which contribute to the production of ANAs. Elucidating the pathways these genes dysregulate will provide critical insight into our understanding of tolerance and how tolerance can be breached.Item Rheumatoid, Rheumatoid-like, and anti-nuclear factors in disease(1965-09-23) Unknown