Expression of intercellular adhesion molecule-1 in UVA-irradiated human skin cells in vitro and in vivo.

Ultraviolet A (UVA) radiation represents an important oxidative stress to human skin and certain forms of oxidative stress have been shown to modulate intercellular adhesion molecule-1 (ICAM-1) expression. ICAM-1 has been shown to play an important part in many immune reactions and the perturbations of this molecule by ultraviolet radiation could have implications in many inflammatory responses. An enhancement immunohistochemical method with avidin/biotin was used for analysing the early effects of UVA radiation on human cell cultures and human skin (340-400 nm). Both in vitro and in vivo data show that ICAM-1 staining in epidermal keratinocytes, which was expressed constitutively, decreased in a UVA dose-dependent manner. The decrease was most noted at 3-6 h following UVA radiation with some ICAM-1 staining returning by 48 h post-UVA. ICAM-1 positive staining in the dermis was specific for vascular structures and was increased 24 h after UVA radiation. Cultured dermal fibroblasts exhibited ICAM-1 staining which increased slightly within 6-48 h post-UVA radiation. As epidermal ICAM-1 expression is depleted following UVA radiation and dermal expression increases due to an increase in the vascular structures, ICAM-1 provides a valuable marker following UVA radiation in human skin that can be readily measured in situ.

Analyses of six homologous proteins of Protochlamydia amoebophila UWE25 encoded by large GC-rich genes (lgr): a model of evolution and concatenation of leucine-rich repeats.

BACKGROUND: Along the chromosome of the obligate intracellular bacteria Protochlamydia amoebophila UWE25, we recently described a genomic island Pam100G. It contains a tra unit likely involved in conjugative DNA transfer and lgrE, a 5.6-kb gene similar to five others of P. amoebophila: lgrA to lgrD, lgrF. We describe here the structure, regulation and evolution of these proteins termed LGRs since encoded by "Large G+C-Rich" genes. RESULTS: No homologs to the whole protein sequence of LGRs were found in other organisms. Phylogenetic analyses suggest that serial duplications producing the six LGRs occurred relatively recently and nucleotide usage analyses show that lgrB, lgrE and lgrF were relocated on the chromosome. The C-terminal part of LGRs is homologous to Leucine-Rich Repeats domains (LRRs). Defined by a cumulative alignment score, the 5 to 18 concatenated octacosapeptidic (28-meric) LRRs of LGRs present all a predicted alpha-helix conformation. Their closest homologs are the 28-residue RI-like LRRs of mammalian NODs and the 24-meres of some Ralstonia and Legionella proteins. Interestingly, lgrE, which is present on Pam100G like the tra operon, exhibits Pfam domains related to DNA metabolism. CONCLUSION: Comparison of the LRRs, enable us to propose a parsimonious evolutionary scenario of these domains driven by adjacent concatenations of LRRs. Our model established on bacterial LRRs can be challenged in eucaryotic proteins carrying less conserved LRRs, such as NOD proteins and Toll-like receptors.

Expression of E-Selectin and Vascular Cell Adhesion Molecule-1 in So-Called 'Negative' Appendices: First Results to Support the Pathological Diagnosis in Borderline Cases.

Background: Since the rate of histologically 'negative' appendices still ranges between 15 and 20%, appendicitis in 'borderline' cases remains a challenging disease. As previously described, cell adhesion molecule expression correlates with different stages of appendicitis. Therefore, it was of interest to determine whether the 'negative' appendix correlated with the absence of E-selectin or vascular cell adhesion molecule-1 (VCAM-1). Methods: Nineteen grossly normal appendices from a series of 120 appendectomy specimens from patients with suspected appendicitis were analysed in frozen sections for the expression of E-selectin and VCAM-1. As control, 5 normal appendices were stained. Results: This study showed a coexpression of E-selectin and VCAM-1 in endothelial cells in early and recurrent appendicitis. In patients with symptoms for less than 6 h, only E-selectin was detected. Cases with fibrosis and luminal obliteration were only positive for VCAM-1. In cases of early appendicitis with symptoms of less than 6 h duration, a discordance between histological and immunohistochemical results was found. Conclusions: This report indicates that E-selectin and VCAM-1 expression could be useful parameters in the diagnosis of appendicitis in borderline cases.

Retinal pigment epithelium protein of 65 kDA gene-linked retinal degeneration is not modulated by chicken acidic leucine-rich epidermal growth factor-like domain containing brain protein/Neuroglycan C/ chondroitin sulfate proteoglycan 5.

PURPOSE: To analyze in vivo the function of chicken acidic leucine-rich epidermal growth factor-like domain containing brain protein/Neuroglycan C (gene symbol: Cspg5) during retinal degeneration in the Rpe65S15;/S15; mouse model of Leber congenital amaurosis. METHODS: We resorted to mice with targeted deletions in the Cspg5 and retinal pigment epithelium protein of 65 kDa (Rpe65) genes (Cspg5S15;/S15;/Rpe65S15;/S15;). Cone degeneration was assessed with cone-specific peanut agglutinin staining. Transcriptional expression of rhodopsin (Rho), S-opsin (Opn1sw), M-opsin (Opn1mw), rod transducin α subunit (Gnat1), and cone transducin α subunit (Gnat2) genes was assessed with quantitative PCR from 2 weeks to 12 months. The retinal pigment epithelium (RPE) was analyzed at P14 with immunodetection of the retinol-binding protein membrane receptor Stra6. RESULTS: No differences in the progression of retinal degeneration were observed between the Rpe65S15;/S15; and Cspg5S15;/S15;/Rpe65S15;/S15; mice. No retinal phenotype was detected in the late postnatal and adult Cspg5S15;/S15; mice, when compared to the wild-type mice. CONCLUSIONS: Despite the previously reported upregulation of Cspg5 during retinal degeneration in Rpe65S15;/S15; mice, no protective effect or any involvement of Cspg5 in disease progression was identified.

Characterization of NALP2 and NALP3 IL-1β processing inflammasomes

Résumé II y a cinq ans, la découverte d'un nouveau domaine, le PYD domaine, lié aux domaines de la mort, a permis la description de la nouvelle famille des NALP protéines. L'analyse structurelle de cette famille de protéines révéla la présence de deux autres domaines, impliqués dans l'oligomerisation, NACHT, et la détection des ligands, Leucine rich repeats ou LRR. Cette architecture protéique est homologue à celle qui est décrite pour les NODs, les Tol1 récepteurs et tes protéines de résistance chez les plantes. Cette homologie suggère une possible implication des NALPs dans la régulation de l'immunité innée. Premièrement, nous avons décrit les composants minimaux qui permettent à l'inflammasomeNALP3 d'activer la caspase pro-inflammatoire, caspase-1. En comparaison à NALP1, NALP3 ne contient pas de FIIND domaine, ni de CARD domaine en C-terminus et n'interagit pas avec caspase-5. Nous avons découvert une protéine très homologue au C-terminus de NALP1, Cardinal, qui se lie au NACHT domaine de NALP2 et NALP3 par l'intermédiaire de son FIIND domaine. Cardinal possède la capacité d'interagir avec caspase-l, mais seul ASC semble être nécessaire à la maturation de la prointerleukine-1β suite à la stimulation de NALP3. Deuxièmement, notre étude s'est concentrée sur la nature du stimulus capable d'induire la formation et l'activation de l'inflammasome-NALP3. Nous avons démontré que l'ajout de muramyl dipeptide (MDP), produit à partir de la digestion enzymatique de peptidoglycaris bactériens, induit à la fois l'expression de la proIL-1β par la voie NOD2 et sa maturation en IL-1β active par la voie NALP3. Bien que le MDP active l'inflammasome-NALP3, il est incapable d'induire la sécrétion de l'IL-1β mature dans la lignée cellulaire THP1, comparé aux monocytes primaires humains. Cette différence pourrait être liée à l'absence, dans les THP1, de la protéine Filamin, qui est proposée d'interagir avec Cardinal. L'implication de NALP3 dans la maturation de l'IL-lb est confirmée suite à la découverte de mutations sur le gène CIAS1/NALP3/cryopyrin associées à trois maladies auto-inflammatoires : le syndrome de Muckle-Wells (MWS), l'urticaire familial au froid (FCU) et le syndrome CINCA/NOMID. Une élévation constitutive de la maturation et de la sécrétion de la proIL-1β en absence de stimulation MDP est détectée dans les macrophages des patients Muckle-Wells. En conclusion, nos études ont démontré que l'inflammasome-NALP3 doit être finement régulé pour éviter une activité incontrôlée qui représente la base moléculaire des symptômes associés aux syndromes auto-inflammatoires liés à NALP3. Summary Five years ago, the description of the NALP family originated from the discovery of a new death-domain fold family, the PYD domain. NALP contains aprotein-protein interaction domain (PYD), an oligomerization domain (NACHT) and a ligand-sensing domain, leucine rich repeats or LRR. This protein architecture shares similarity with receptors involved in immunity, such as NODS, Toll receptors (TLRs) and related plant resistance proteins, and points to an important role of NALPs in defense mechanisms. We first described the minimal complex involved in the pro-inflammatory Interleukin-1beta (IL-1β) cytokine maturation, called the inflammasome, which contains NALP3. In contrast to NALP1, NALP3, like other members of the NALP family, is devoid of C-terminal FIIND and CARD domains and does not interact with the pro-inflammatory caspase-5. Interestingly, a homolog of the C-terminal portion of NALP1 was found in the human genome and was named Cardinal. We found that NALP2 and NALP3 interact with the CARD-containing proteins Cardinal. Cardinal is able to bind to caspase-1 but is not required for IL-1β maturation through NALP3 activation, as demonstrated for the adaptor ASC. Secondly, our study focused on the stimuli involved in the activation of the NALP3 inflammasome. MDP was shown to induce the expression of proIL1β through NOD2 and then the maturation into active IL-1β by activation of the NALP3 inflammasome. However, in the monocytic THP1 cell line, secretion of IL-1β upon MDP stimulation seems to be independent of the inflammasome activation compared to human primary monocytes. This difference might be linked to a Cardinal-interacting protein, filamin. Until now, the role of Cardinal and filamin is still unknown and remains to be elucidated. Finally, mutations in the NALP3/cryopyrin/CIAS1 gene are associated with three autoinflammatory diseases: Muckle-Wells syndrome, familial cold autoinflammatory syndrome, and CINCA. Constitutive, elevated IL-1β maturation and secretion, even in the absence of MDP stimulation, was observed in macrophages from Muckle-Wells patients and confirmed a key role for the NALP3 inflammasome in innate immunity In conclusion, our studies describes the formation of the NALP3 inflammasome and suggests that this complex has to be tightly regulated to avoid an increased deregulated inflammasome activity that is the molecular basis for the symptoms associated with NALP3-dependent autoinflammatory disorders.

Cloning of an interferon-gamma regulated human melanoma-associated antigen: identity to the intercellular adhesion molecule ICAM-1.

The human melanoma-associated antigen identified by the monoclonal antibody (mAb) Me14-D12 is a cell surface protein whose expression is induced by interferon-gamma (IFN-gamma). We have recently reported the molecular cloning of a genomic probe specific for the gene and mRNA of this protein. By screening with the genomic probe, we have now isolated a full length 3.0 kb cDNA from a Raji cell line-derived lambda-gt10 library. Sequence analysis of this cDNA showed a 99.8% homology with the intercellular adhesion molecule-1 (ICAM-1). Mouse Ltk- cells stably transfected with the human cDNA clone were found to express the ICAM-1 antigenic determinants detected by mAb Me14-D12 and a reference anti-ICAM-1 mAb, as judged by surface immunofluorescence. Immunoprecipitation of surface-iodinated proteins with mAb Me14-D12 revealed the presence of a 90 kD molecule with identical mobility to ICAM-1. In addition, mAb Me14-D12 could inhibit the phorbolester-stimulated aggregation of U937 cells. The findings show that the human melanoma-associated Me14-D12 antigen is the adhesion molecule ICAM-1.

Matrix metalloproteinase 9 (MMP-9/gelatinase B) proteolytically cleaves ICAM-1 and participates in tumor cell resistance to natural killer cell-mediated cytotoxicity.

Shedding of intercellular adhesion molecule 1 (ICAM-1) is believed to play a role in tumor cell resistance to cell-mediated cytotoxicity. However, the mechanism whereby ICAM-1 is shed from the surface of tumor cells remains unclear. In this study, we have addressed the possibility that matrix metalloproteinases are implicated in ICAM-1 shedding. Our observations suggest a functional relationship between ICAM-1 and matrix metalloproteinase 9 (MMP-9) whereby ICAM-1 provides a cell surface docking mechanism for proMMP-9, which, upon activation, proteolytically cleaves the extracellular domain of ICAM-1 leading to its release from the cell surface. MMP-9-dependent shedding of ICAM-1 is found to augment tumor cell resistance to natural killer (NK) cell-mediated cytotoxicity. Taken together, our observations propose a mechanism for ICAM-1 shedding from the cell surface and provide support for MMP involvement in tumor cell evasion of immune surveillance.

In vitro characterization of immune-related properties of human fetal bone cells for potential tissue engineering applications.

We describe herein some immunological properties of human fetal bone cells recently tested for bone tissue-engineering applications. Adult mesenchymal stem cells (MSCs) and osteoblasts were included in the study for comparison. Surface markers involved in bone metabolism and immune recognition were analyzed using flow cytometry before and after differentiation or treatment with cytokines. Immunomodulatory properties were studied on activated peripheral blood mononuclear cells (PBMCs). The immuno-profile of fetal bone cells was further investigated at the gene expression level. Fetal bone cells and adult MSCs were positive for Stro-1, alkaline phosphatase, CD10, CD44, CD54, and beta2-microglobulin, but human leukocyte antigen (HLA)-I and CD80 were less present than on adult osteoblasts. All cells were negative for HLA-II. Treatment with recombinant human interferon gamma increased the presence of HLA-I in adult cells much more than in fetal cells. In the presence of activated PBMCs, fetal cells had antiproliferative effects, although with patterns not always comparable with those of adult MSCs and osteoblasts. Because of the immunological profile, and with their more-differentiated phenotype than of stem cells, fetal bone cells present an interesting potential for allogeneic cell source in tissue-engineering applications.

Caspase-1 autoproteolysis is differentially required for NLRP1b and NLRP3 inflammasome function.

Inflammasomes are caspase-1-activating multiprotein complexes. The mouse nucleotide-binding domain and leucine rich repeat pyrin containing 1b (NLRP1b) inflammasome was identified as the sensor of Bacillus anthracis lethal toxin (LT) in mouse macrophages from sensitive strains such as BALB/c. Upon exposure to LT, the NLRP1b inflammasome activates caspase-1 to produce mature IL-1β and induce pyroptosis. Both processes are believed to depend on autoproteolysed caspase-1. In contrast to human NLRP1, mouse NLRP1b lacks an N-terminal pyrin domain (PYD), indicating that the assembly of the NLRP1b inflammasome does not require the adaptor apoptosis-associated speck-like protein containing a CARD (ASC). LT-induced NLRP1b inflammasome activation was shown to be impaired upon inhibition of potassium efflux, which is known to play a major role in NLRP3 inflammasome formation and ASC dimerization. We investigated whether NLRP3 and/or ASC were required for caspase-1 activation upon LT stimulation in the BALB/c background. The NLRP1b inflammasome activation was assessed in both macrophages and dendritic cells lacking either ASC or NLRP3. Upon LT treatment, the absence of NLRP3 did not alter the NLRP1b inflammasome activity. Surprisingly, the absence of ASC resulted in IL-1β cleavage and pyroptosis, despite the absence of caspase-1 autoprocessing activity. By reconstituting caspase-1/caspase-11(-/-) cells with a noncleavable or catalytically inactive mutant version of caspase-1, we directly demonstrated that noncleavable caspase-1 is fully active in response to the NLRP1b activator LT, whereas it is nonfunctional in response to the NLRP3 activator nigericin. Taken together, these results establish variable requirements for caspase-1 cleavage depending on the pathogen and the responding NLR.

Metastatic leishmaniasis. A chronic inflammatory response to Leishmania's viral endosymbiont.

Leishmania parasites have been plaguing humankind for centuries as a range of skin diseases named the cutaneous leishmaniases (CL). Carried in a hematophagous sand fly, Leishmania usually infests the skin surrounding the bite site, causing a destructive immune response that may persist for months or even years. The various symptomatic outcomes of CL range from a benevolent self- healing reddened bump to extensive open ulcerations, resistant to treatment and resulting in life- changing disfiguration. Many of these more aggressive outcomes are geographically isolated within the habitats of certain Neotropical Leishmania species; where about 15% of cases experience metastatic complications. However, despite this correlation, genetic analysis has revealed no major differences between species causing the various disease forms. We have recently identified a cytoplasmic dsRNA virus within metastatic L. guyanensis parasites that acts as a potent innate immunogen capable of worsening lesionai inflammation and prolonging parasite survival. The dsRNA genome of Leishmania RNA virus (LRV) binds and stimulates Toll-Like-Receptor-3 (TLR3), inducing this destructive inflammation, which we speculate as a factor contributing to the development of metastatic disease. This thesis establishes the first experimental model of LRV-mediated leishmanial metastasis and investigates the role of non-TLR3 viral recognition pathways in LRV-mediated pathology. Viral dsRNA can be detected by various non-TLR3 pattern recognition receptors (PRR); two such PRR groups are the RLRs (Retinoic acid-inducible gene 1 like receptors) and the NLRs (nucleotide- binding domain, leucine-rich repeat containing receptors). The RLRs are designed to detect viral dsRNA in the cytoplasm, while the NLRs react to molecular "danger" signals of cell damage, often oligomerizing into molecular scaffolds called "inflammasomes" that activate a potent inflammatory cascade. Interestingly, we found that neither RLR signalling nor the inflammasome pathway had an effect on LRV-mediated pathology. In contrast, we found a dramatic inflammasome independent effect for the NLR family member, NLRP10, where a knockout mouse model showed little evidence of disease. This phenotype was mimicked in an NLR knockout with which NLRP10 is known to interact: NLRC2. As this pathway induces the chronic inflammatory cell lineage TH17, we investigated the role of its key chronic inflammatory cytokine, IL-17A, in human patients infected by L. guyanensis. Indeed, patients infected with LRV+ parasites had a significantly increased level of IL-17A in lesionai biopsies. Interestingly, LRV presence was also associated with a significant decrease in the correlate of protection, IFN-y. This association was repeated in our murine model, where after we were able to establish the first experimental model of LRV-dependent leishmanial metastasis, which was mediated by IL-17A in the absence of IFN-y. Finally, we tested a new inhibitor of IL-17A secretion, SR1001, and reveal its potential as a Prophylactic immunomodulator and potent parasitotoxic drug. Taken together, these findings provide a basis for anti-IL-17A as a feasible therapeutic intervention to prevent and treat the metastatic complications of cutaneous leishmaniasis. -- Les parasites Leishmania infectent l'homme depuis des siècles causant des affections cutanées, appelées leishmanioses cutanées (LC). Le parasite est transmis par la mouche des sables et réside dans le derme à l'endroit de la piqûre. Au niveau de la peau, le parasite provoque une réponse immunitaire destructrice qui peut persister pendant des mois voire des années. Les symptômes de LC vont d'une simple enflure qui guérit spontanément jusqu' à de vastes ulcérations ouvertes, résistantes aux traitements. Des manifestations plus agressives sont déterminées par les habitats géographiques de certaines espèces de Leishmania. Dans ces cas, environ 15% des patients développent des lésions métastatiques. Aucun «facteur métastatique» n'a encore été trouvé à ce jour dans ces espèces. Récemment, nous avons pu identifier un virus résidant dans certains parasites métastatiques présents en Guyane française (appelé Leishmania-virus, ou LV) et qui confère un avantage de survie à son hôte parasitaire. Ce virus active fortement la réponse inflammatoire, aggravant l'inflammation et prolongeant l'infection parasitaire. Afin de diagnostiquer, prévenir et traiter ces lésions, nous nous sommes intéressés à identifier les composants de la voie de signalisation anti-virale, responsables de la persistance de cette inflammation. Cette étude décrit le premier modèle expérimental de métastases de la leishmaniose induites par LV, et identifie plusieurs composants de la voie inflammatoire anti-virale qui facilite la pathologie métastatique. Contrairement à l'homme, les souris de laboratoire infectées par des Leishmania métastatiques (contenant LV, LV+) ne développent pas de lésions métastatiques et guérissent après quelques semaines d'infection. Après avoir analysé un groupe de patients atteints de leishmaniose en Guyane française, nous avons constaté que les personnes infectées avec les parasites métastatiques LV+ avaient des niveaux significativement plus faibles d'un composant immunitaire protecteur important, appelé l'interféron (IFN)-y. En utilisant des souris génétiquement modifiées, incapables de produire de l'IFN-y, nous avons observé de telles métastases. Après inoculation dans le coussinet plantaire de souris IFN-y7" avec des parasites LV+ ou LV-, nous avons démontré que seules les souris infectées avec des leishmanies ayant LV développent de multiples lésions secondaires sur la queue. Comme nous l'avons observé chez l'homme, ces souris sécrètent une quantité significativement élevée d'un composant inflammatoire destructeur, l'interleukine (IL)-17. IL-17 a été incriminée pour son rôle dans de nombreuses maladies inflammatoires chroniques. On a ainsi trouvé un rôle destructif similaire pour l'IL-17 dans la leishmaniose métastatique. Nous avons confirmé ce rôle en abrogeant IL-17 dans des souris IFN-y7- ce qui ralentit l'apparition des métastases. Nous pouvons donc conclure que les métastases de la leishmaniose sont induites par l'IL-17 en absence d'IFN-v. En analysant plus en détails les voies de signalisation anti-virale induites par LV, nous avons pu exclure d'autres voies d'activation de la réponse inflammatoire. Nous avons ainsi démontré que la signalisation par LV est indépendante de la signalisation inflammatoire de type « inflammasome ». En revanche, nous avons pu y lier plusieurs autres molécules, telles que NLRP10 et NLRC2, connues pour leur synergie avec les réponses inflammatoires. Cette nouvelle voie pourrait être la cible pour des médicaments inhibant l'inflammation. En effet, un nouveau médicament qui bloque la production d'IL-17 chez la souris s'est montré prometteur dans notre modèle : il a réduit le gonflement des lésions ainsi que la charge parasitaire, indiquant que la voie anti-virale /inflammatoire est une approche thérapeutique possible pour prévenir et traiter cette infection négligée.

Genetics of Parkinson disease and essential tremor.

Purpose of review: Elucidating the genetic background of Parkinson disease and essential tremor is crucial to understand the pathogenesis and improve diagnostic and therapeutic strategies. Recent findings: A number of approaches have been applied including familial and association studies, and studies of gene expression profiles to identify genes involved in susceptibility to Parkinson disease. These studies have nominated a number of candidate Parkinson disease genes and novel loci including Omi/HtrA2, GIGYF2, FGF20, PDXK, EIF4G1 and PARK16. A recent notable finding has been the confirmation for the role of heterozygous mutations in glucocerebrosidase (GBA) as risk factors for Parkinson disease. Finally, association studies have nominated genetic variation in the leucine-rich repeat and Ig containing 1 gene (LINGO1) as a risk for both Parkinson disease and essential tremor, providing the first genetic evidence of a link between the two conditions. Summary: Although undoubtedly genes remain to be identified, considerable progress has been achieved in the understanding of the genetic basis of Parkinson disease. This same effort is now required for essential tremor. The use of next-generation high-throughput sequencing and genotyping technologies will help pave the way for future insight leading to advances in diagnosis, prevention and cure.

LINGO1 and LINGO2 variants are associated with essential tremor and Parkinson disease.

Genetic variation in the leucine-rich repeat and Ig domain containing 1 gene (LINGO1) was recently associated with an increased risk of developing essential tremor (ET) and Parkinson disease (PD). Herein, we performed a comprehensive study of LINGO1 and its paralog LINGO2 in ET and PD by sequencing both genes in patients (ET, n=95; PD, n=96) and by examining haplotype-tagging single-nucleotide polymorphisms (tSNPs) in a multicenter North American series of patients (ET, n=1,247; PD, n= 633) and controls (n=642). The sequencing study identified six novel coding variants in LINGO1 (p.S4C, p.V107M, p.A277T, p.R423R, p.G537A, p.D610D) and three in LINGO2 (p.D135D, p.P217P, p.V565V), however segregation analysis did not support pathogenicity. The association study employed 16 tSNPs at the LINGO1 locus and 21 at the LINGO2 locus. One variant in LINGO1 (rs9652490) displayed evidence of an association with ET (odds ratio (OR) =0.63; P=0.026) and PD (OR=0.54; P=0.016). Additionally, four other tSNPs in LINGO1 and one in LINGO2 were associated with ET and one tSNP in LINGO2 associated with PD (P<0.05). Further analysis identified one tSNP in LINGO1 and two in LINGO2 which influenced age at onset of ET and two tSNPs in LINGO1 which altered age at onset of PD (P<0.05). Our results support a role for LINGO1 and LINGO2 in determining risk for and perhaps age at onset of ET and PD. Further studies are warranted to confirm these findings and to determine the pathogenic mechanisms involved.

Differential migration of in vivo primed B and T lymphocytes to lymphoid and non-lymphoid organs.

Our study describes tissue-specific migration of T and B cells during a localized anti-viral immune response. After mouse mammary tumor virus (MMTV) injection, B lymphocytes of the draining lymph node become infected and present a retroviral superantigen to CD4(+) T lymphocytes. Infected B cells receive superantigen-mediated help in a fashion comparable to classical immune responses. To investigate the fate of T and B lymphocytes that had interacted via cognate help in the same peripheral lymph node microenvironment we adoptively transferred them into naive recipients. Here we show that MMTV-infected B cells and superantigen-stimulated T cells were programmed to migrate to distinct sites of the body. Plasmablasts but not T cells migrated to the mammary gland and activated alpha4beta1 integrins were found to have a crucial role in the migration to the mammary gland. In contrast, T cells had a much higher affinity for secondary lymphoid organs and large intestine. This demonstrates that upon antigen-driven B and T lymphocyte interaction in the local draining lymph node a subset-specific homing program for B and T lymphocytes is induced.

Alum interaction with dendritic cell membrane lipids is essential for its adjuvanticity.

As an approved vaccine adjuvant for use in humans, alum has vast health implications, but, as it is a crystal, questions remain regarding its mechanism. Furthermore, little is known about the target cells, receptors, and signaling pathways engaged by alum. Here we report that, independent of inflammasome and membrane proteins, alum binds dendritic cell (DC) plasma membrane lipids with substantial force. Subsequent lipid sorting activates an abortive phagocytic response that leads to antigen uptake. Such activated DCs, without further association with alum, show high affinity and stable binding with CD4(+) T cells via the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1). We propose that alum triggers DC responses by altering membrane lipid structures. This study therefore suggests an unexpected mechanism for how this crystalline structure interacts with the immune system and how the DC plasma membrane may behave as a general sensor for solid structures.