Immunogenetics

Martín, M.; Martinez, Alfonso; Mendoza, J.; Taxonera, Carlos; Díaz-Rubio, Manuel; Fernández-Arquero, Miguel; Concha, Emilio; Urcelay, Elena

doi: 10.1007/s00251-007-0255-1pmid: 17955236

The great amount of nitric oxide (NO) produced by the inducible isoform of NO synthase (iNOS) exerts deleterious effects, and iNOS expression is raised in the colonic mucosa of inflammatory bowel disease (IBD) patients. This is the first association analysis of polymorphisms within the NOS2A extended gene with IBD susceptibility. We analyzed 336 patients of Crohn’s disease (CD), 355 of ulcerative colitis (UC), and 536 healthy controls from a Spanish population. We tested a (CCTTT)n microsatellite, a (−/TAAA) insertion, and two single nucleotide polymorphisms (SNPs) flanking them (rs2779251 and rs2779248) in the NOS2A promoter, together with two SNPs in the coding region: one within exon 10, D385D (rs1137933), and another mapping to exon 16, S608L (rs2297518). Analysis of these markers evidenced differences among IBD patients and healthy controls. Allele (CCTTT) 13 is related to higher UC risk (p = 0.001; odds ratio [OR] [95% confidence interval, CI] = 1.64 [1.20–2.23]). Carriers of minor alleles of the two promoter SNPs analyzed showed an association with UC predisposition, and common allele homozygotes of the two exonic SNPs were more frequent among CD patients than among controls. Concordantly, one out of the three haplotypes carrying both exonic risk alleles was found to increase CD susceptibility (p = 0.007; OR [95%CI] = 1.74 [1.13–2.67]). Therefore, the NOS2A gene seems to be involved in IBD aetiology.

Lan, Qing; Shen, Min; Garcia-Rossi, Dino; Chanock, Stephen; Zheng, Tongzhang; Berndt, Sonja; Puri, Vinita; Li, Guilan; He, Xingzhou; Welch, Robert; Zahm, Shelia; Zhang, Luoping; Zhang, Yawei; Smith, Martyn; Wang, Sophia; Chiu, Brian;

Konno, Akihiro; Takiguchi, Mitsuyoshi; Takada, Kensuke; Usami, Takeshi; Azumi, Kaoru; Kubota, Hisayo; Inaba, Mutsumi; Saegusa, Junzo; Kon, Yasuhiro

doi: 10.1007/s00251-007-0244-4pmid: 17938903

Sjögren’s syndrome (SS) is caused by an autoimmune sialodacryoadenitis, and up to 5% of patients with SS develop malignant B cell growth. The IQI mouse is a spontaneous model of primary SS in which B cells are the dominant cellular subpopulation among mononuclear infiltrates in sialitis lesions. Understanding the genetic control of aberrant B cell growth in IQI mice may help elucidate the genetic mechanisms involved in B-lineage hyperplasia leading to malignant transformation in human SS. B cell-dominant infiltration in the submandibular glands of 6-month-old IQI and C57BL/6 (B6) mice and their F1 and F2 progenies was quantified as B-lymphocytic sialitis score, and a genome-wide scan of 179 (IQI x B6) F2 females was performed to identify a quantitative trait locus (QTL) controlling this phenotype. A QTL significantly associated with variance in B-lymphocytic sialitis score was mapped to the D6Mit138 marker (position of 0.68cM) on proximal chromosome 6, with a logarithm of odds score of 4.3 (p = 0.00005). This QTL, named autoimmune sialitis in IQI mice, associated locus 1 (Asq1), colocalized with Islet cell autoantigen 1 (Ica1), which encodes a target protein of the immune processes that define the pathogenesis of primary SS in humans and in the nonobese diabetic mouse model.

Jackson, Andrew; McLure, Craig; Dawkins, Roger; Keating, Peter

doi: 10.1007/s00251-007-0251-5pmid: 17943278

We describe a novel extension of the Genomic Matching Technique (GMT) that defines haplotypes of the mannose binding lectin (MBL) region in Zebrafish (D. rerio). Four ancestral haplotypes have been identified to date, with at least one of these demonstrating a significant increase in resistance to L. anguillarum. MBL activates the lectin pathway of the complement system and stimulates the development of the complement cascade and the Membrane Attack Complex. Polymorphisms in humans have been associated with increased susceptibility and severity to a number of pathogenic organisms. As teleosts have a relatively immature acquired immune system, polymorphisms within MBL and other innate defence genes are likely to be critical in defining their susceptibility/resistance to various pathogenic organisms. We report multiple copies of MBL-like genes in D. rerio, with up to three copies tightly linked within a cluster spanning ∼15 kb on chromosome 2. Genomic analysis suggests that duplication, retroviral insertion and possibly gene mutation and/or deletion have been key factors in the evolution of this cluster. Molecular analysis has revealed extensive polymorphism, including at least five distinct amplicons and haplospecific gene copy number variation. This study demonstrates polymorphism within a critical component of the teleost innate immune system. The polymorphisms and the haplotypes encoding the unique variants are likely to be informative in defining susceptibility/resistance to infectious agents commonly encountered within aquatic environments. Future investigations will define other important haplotypes and transfer the knowledge to other finfish species, thereby enabling selection of broodstock for the aquaculture industry.

Tsutsui, Shigeyuki; Nakamura, Osamu; Watanabe, Tasuku

doi: 10.1007/s00251-007-0254-2pmid: 17924104

We report here the first evidence for interleukin-17, a pro-inflammatory cytokine, in cyclostomes. To detect the novel molecules involved in the immune response in the skin of the lamprey Lethenteron japonicum, subtractive hybridization was performed with 6-h-cultured skin cells with or without lipopolysaccharide (LPS). In approximately 100 partially sequenced clones analyzed, we identified an interesting sequence similar to that of the IL-17 genes in teleosts and mammals. Subsequent rapid amplification of cDNA ends was used to obtain the cDNA of lamprey IL-17 (LampIL-17) that contains a 519-bp open reading frame encoding a mature protein of 154 amino acids and a 19-residue NH2-terminal signal peptide. The phylogenetic tree indicated that LampIL-17 is clustered into IL-17D, which is a subgroup of the IL-17 family. Southern blot analysis showed that the lamprey harbors a single copy of the LampIL-17 gene in its genome. The LampIL-17 gene was constitutively expressed in most tissues examined as well as in the skin, where the basal layer epithelial cells expressed LampIL-17 mRNA. Real-time-polymerase chain reaction (RT-PCR) demonstrated that the LampIL-17 gene expression in LPS-stimulated skin cells tended to be greater than that in non-stimulated cells. These results suggest that LampIL-17 is responsible for defense against bacterial infections in the lamprey skin.

Zhang, Si-Ming; Zeng, Yong; Loker, Eric

doi: 10.1007/s00251-007-0245-3pmid: 17805526

Peptidoglycan (PGN) recognition proteins (PGRPs) and gram-negative bacteria binding proteins (GNBPs) play an essential role in Toll/Imd signaling pathways in arthropods. The existence of homologous pathways involving PGRPs and GNBPs in other major invertebrate phyla such as the Mollusca remains unclear. In this paper, we report four full-length PGRP cDNAs and one full-length GNBP cDNA cloned from the snail Biomphalaria glabrata, the intermediate host of the human blood fluke Schistosoma mansoni, designated as BgPGRPs and BgGNBP, respectively. Three transcripts are generated from a long form PGRP gene (BgPGRP-LA) by alternative splicing and one from a short form PGRP gene (BgPGRP-SA). BgGNBP encodes a putative secreted protein. Northern blots demonstrated that expression of BgPGRP-SA and BgGNBP was down-regulated in B. glabrata at 6 h after exposure to three types of microbes. No significant changes in expression were observed in snails at 2 days post-exposure (dpe) to the trematodes Echinostoma paraensei or S. mansoni. However, up-regulation of BgPGRP-SA in M line snails at later time points of infection with E. paraensei (i.e., 12 and 17 dpe) was observed. Our study revealed that exposure to either microbes or trematodes did not alter the expression levels of BgPGRP-LAs, which were consistently low. This study provides new insights into the potential pathogen recognition capabilities of molluscs, indicates that further studies of the Toll/Imd pathways in this phylum are in order, and provides additional ways to judge the importance of this pathway in the evolution of internal defense across the animal phyla.