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Contact hypersensitivity (CHS) is a hapten-specific skin inflammation mediated by T cells that recognize haptenated peptides presented by major histocompatibility complex (MHC) class I and class II molecules on antigen-presenting cells (APCs). CHS is a self-limited inflammation of short duration which peaks at 24 hours after challenge. CHS spontaneously resolves in a few days, suggesting the existence of potent downregulatory mechanisms which control and/or block the effector cells of contact sensitivity (CS).In a recent Review article on the pathophysiology of CHS, Stephan Grabbe and Thomas Schwarz stressed the differences between CHS and classical delayed-type hypersensitivity (DTH) reactions to proteins [1xGrabbe, S. and Schwarz, T. Immunol. Today. 1998; 19: 37–44Abstract | Full Text PDF | PubMed | Scopus (413)See all References[1]. Whereas DTH responses are mediated by CD4+ effector cells, it has been reported that the CHS inflammatory reaction is mediated by CD8+ effector cells and that CD4+ T cells are endowed with downregulatory properties [2xBour, H., Peyron, E., Gaucherand, M. et al. Eur. J. Immunol. 1995; 25: 3006–3010Crossref | PubMedSee all References, 3xXu, H., Diiulio, N.A., and Fairchild, R.L. J. Exp. Med. 1996; 183: 1001–1012Crossref | PubMedSee all References]. These observations raised the question of the nature of the APCs responsible for priming the hapten-specific CD4+ and CD8+ T cells. Although epidermal dendritic cells (DCs) (Langerhans cells; LCs) have been shown to induce effector cells of CHS, it was hypothesized that they were not responsible for the priming of downregulatory CD4+ cells, instead a special type of APC, lacking appropriate costimulatory signals, could be involved in the phenomenon [1xGrabbe, S. and Schwarz, T. Immunol. Today. 1998; 19: 37–44Abstract | Full Text PDF | PubMed | Scopus (413)See all References[1].We recently addressed the question of the nature of the APC responsible for the priming of downregulatory T cells, in the murine model of CHS induced by treatment with the contact allergen 2,4-dinitrofluorobenzene (DNFB) in which CD8+ cells are effector cells of CS and CD4+ cells behave as downregulatory cells [2xBour, H., Peyron, E., Gaucherand, M. et al. Eur. J. Immunol. 1995; 25: 3006–3010Crossref | PubMedSee all References[2]. Mature DCs were either generated from the skin after overnight culture in granulocyte–macrophage colony-stimulating factor (GM-CSF) or generated in vitro from bone marrow progenitors of wild-type C57BL/6 as well as of β2-microglobulin-deficient (β2-m−/−) and Aβ−/− mice, which are genetically deficient in MHC class I or MHC class II molecules, respectively. These DCs, expressing a mature DC phenotype (CD11c+, DEC-205+, B7-1+, B7-2+, CD40+ and MHC class IIhi), were haptenated in vitro and injected into naive C57BL/6 wild-type recipients which five days later received a cutaneous application of DNFB on the ears. These experiments demonstrated that MHC class I molecules on DCs were mandatory for the induction of CHS reaction inasmuch as DCs recovered from wild-type C57BL/6 [class I+/class II+ (I+/II+)] and Aβ−/− (I+/II−) mice, but not from β2-m−/− (I−/II+), could prime for CHS (Ref. [4xKrasteva, M., Kehren, J., Horand, F. et al. J. Immunol. 1998; 160: 1181–1190PubMedSee all References[4]). Although II+/I− DCs could not sensitize for CS they could prime for hapten-specific CD4+ T cells in the lymphoid organs. More importantly, haptenated II+/I− DCs could induce a down-regulation of CS reaction when injected in wild-type C57BL/6 recipient mice at the time of cutaneous sensitization. Thus, the same type of APC, i.e. mature DCs, which have the remarkable property of presenting exogenous antigens on both MHC class I and MHC class II molecules [5xShen, Z.H., Reznikoff, G., Dranoff, G., and Rock, K.L. J. Immunol. 1997; 158: 2723–2730PubMedSee all References[5], can simultaneously and independently prime for MHC class I-restricted effectors and MHC class II-restricted downregulatory T cells [4xKrasteva, M., Kehren, J., Horand, F. et al. J. Immunol. 1998; 160: 1181–1190PubMedSee all References[4]. It is most likely that skin LCs are involved in processing of haptens bound on self or exogenous proteins into peptides associated to MHC class I and MHC class II molecules [6xLepoittevin, J.P. and Leblond, I. Eur. J. Dermatol. 1997; 7: 151–154See all References[6]and that upon migration to the draining lymph nodes they become efficient in activation of both CD4+ and CD8+ T hapten-specific precursors. Finally, these data suggest that targeting haptens on MHC class II molecules on epidermal DCs could be used to induce antigen-specific tolerance in CHS.

Les pemphigus sont des maladies auto-immunes des desmosomes (jonctions entre les keratinocytes de l'epiderme). La perte de l'adherence entre keratinocytes entraine la formation de bulles cutanees intra-epidermiques. La connaissance des auto-antigenes du desmosome a permis une meilleure classification nosologique des pemphigus. Les bulles cutanees sont profondes dans le pemphigus vulgaire ou l'antigene desmosomial est la desmogleine 3, superficielles dans le pemphigus superficiel ou l'auto-antigene est la desmogleine 1. Deux nouvelles entites ont ete recemment decrites : les pemphigus, ou pustuloses intra-epidermiques, a IgA, ou les auto-antigenes sont les desmocollines, et les pemphigus paraneoplasiques dans lesquels les auto-antigenes sont multiples (desmoplakines, antigene de la pemphigoide bulleuse...). Une association forte avec certains haplotypes (HLA-DR4 et HLA-DR6) suggere que chez des sujets predisposes exposes a certains antigenes de l'environnement, il y aurait production d'anticorps capables de reactions croisees avec des proteines desmosomiales.

La jonction dermo-epidermique et les desmosomes cooperent pour assurer la resistance de la peau, la premiere en ancrant solidement l'epiderme au derme et les seconds en liant les keratinocytes entre eux. Or, les desmosomes et des constituants de la jonction dermo-epidermique (les hemidesmosomes et les fibrilles d'ancrage) sont fortement antigeniques et deviennent la cible d'auto-anticorps dans les trois principales dermatoses auto-immunes bulleuses: les pemphigus, la pemphigoide bulleuse et l'epidermolyse bulleuse acquise. Les antigenes reconnus par les autoanticorps de la pemphigoide bulleuse et de l'epidermolyse bulleuse acquise sont maintenant bien caracterises et leurs genes sont clones

Resume Les auteurs font une revue des traitements medicamenteux des phenomenes de Raynaud secondaires des connectivites et de la maladie de Raynaud. De nombreuses substances medicamenteuses ont ete essayees, dont les derives nitres, les inhibiteurs calciques, les alpha-bloquants, les inhibiteurs de l'enzyme de conversion de l'angiotensine, les prostaglandines E 1 , E 2 et I 2 , et la ketanserine . Les traitements proposes sont d'une efficacite souvent inconstante et partielle. Les indications sont discutees selon le mode evolutif et la cause du syndrome de Raynaud.

International audience; An indicator gene for detection and quantitation of RNA-mediated transposition was constructed (neoRT). It was inserted into a Moloney murine leukemia provirus (Mo-MLV) deleted for the envelope gene to test for intracellular transposition of defective retroviruses [Mo-MLV(neo)RT]. NeoRT contains the selectable neo gene (which confers resistance to the drug G418), inactivated by a polyadenylylation sequence inserted between the neo promotor and coding sequence. The polyadenylylation sequence is flanked (on the antisense strand of the DNA) by a donor and an acceptor splice site so as to be removed upon passage of the provirus through an RNA intermediate. 3T3 cells transfected with the defective Mo-MLV(neo)RT provirus are sensitive to G418. After trans-complementation with Mo-MLV, viral transcripts confer resistance to G418 upon infection of test cells. In the resistant cells, the polyadenylylation sequence has been removed, as a result in most cases of precise splicing of the intronic domain. Retrotransposition of the defective Mo-MLV(neo)RT provirus was demonstrated by submitting transfected G418-sensitive clones to selection. Between 1 and 10 G418-resistant clones were obtained per 10(7) cells. Several possess additional copies, with evidence for precise removal of the intronic domain. By using target test cells in coculture experiments, extracellular intermediates of retrotransposition could not be detected.

International audience; We propose a new screening system of drugs capable of inactivating retroviruses by interfering with the binding, entry into the cell, uncoating, reverse transcription, migration into the nucleus or integration of the retrovirus. It is based on the utilization of recombinant retroviruses which can be detected in single cells by the expression of a LacZ reporter gene. It allows simple and rapid quantification of the number of infectious viral particles. The screening system can then be used to precisely define the period sensitive to the drug.

Embryonal carcinoma (EC) cells and differentiated derivatives grown in tissue culture have rather similar amounts of actin and tubulin. Indirect immunofluorescent microscopy with antibodies to actin shows striking differences in the actin organization in the different teratocarcinoma derivatives. In the EC cells, actin is found predominantly in ruffles and in surface protrusions, as well as in the cytoplasm, but microfilament bundles are not seen. Some of the differentiated clones contain strongly stained microfilament bundles; others contain actin arrangements which appear to be characteristic of the particular cell type. Indirect immunofluorescence microscopy with antibody to tubulin suggests that cytoplasmic microtubules are present both in the EC cells and in the various differentiated states studied. However, the ease with which microtubules can be documented is dependent on how cells are spread on the substratum. During in vitro differentiation of EC cells, changing patterns of actin distribution appear. Cells at the edge of the colony show the characteristic changes in microfilament and microtubular organization before those in the center.

Peripheral blood lymphocytes from 16 patients with sarcoidosis (9 patients with skin sarcoids, 7 patients with erythema nodosum and bilateral hilar adenopathy) and cutaneous anergy and from 23 age-matched healthy controls were characterized by reactivity with monoclonal antibodies OK.T3, OKT4, OKT8 directed to surface antigens of T lymphocytes, helper-inducer and suppressor-cytotoxic Tcell subsets, respectively. In contrast to healthy controls, patients with sarcoidosis had reduced percentages of OKT3+, OKT4+ and OKT8 +cells and a major decrease in the OKT8 + (suppressor) subset. However, these changes were significant only in the group of patients with acute sarcoidosis (erythema nodosum). This abnormal T cell distribution correlates with the alterations in cell-mediated immunity previously observed and suggests the presence of a defective circulating suppressor T cell activity in acute sarcoidosis.

In this study we treated 6 patients with epidermotropic cutaneous T cell lymphoma (CTCL) with intermediate doses of recombinant alpha 2a interferon (18–100 × 106 IU/week) for 2–6 months. One patient experienced complete clinical remission in spite of a persistent dense lymphocytic skin infiltrate. One patient was markedly improved and 2 patients were moderately improved. The clinical condition of the 2 remaining patients was unchanged by interferon treatment. In all cases lesions relapsed a few weeks after treatment was discontinued. This study shows that interferon can be used to treat epidermotropic CTCL. However, a 2- to 6-month treatment using moderate doses did not lead to the high percentage of remission previously reported by others with high doses of recombinant alpha 2a interferon, for longer periods. This result suggests that interferon should be used at high doses and/or for long time periods for clinical improvement of CTCL patients.

From a local series of long-term renal transplant patients and a survey of the literature, some of the viral infections associated with immunosuppressive treatments are discussed in relation to the duration, type, and magnitude of immunosuppression. Special emphasis is put on chronic viral hepatitis, warts and other papova virus infections associated with benign or malignant skin tumors, herpes virus infections and the sequential steps of serum immunoglobulin abnormalities which may culminate in lymphoma or infectious lymphoproliferative syndromes. Finally the distinct features of iatrogenic Kaposi's sarcoma are described in comparison with other forms of this disease. Some of these disorders fit well with the multi-step hypothesis of carcinogenesis. In most situations the pathogenesis of these complications appears to be multifactorial and the contribution of each immunosuppressive agent is difficult to ascertain, inasmuch as other factors such as initial virological status, allogenic stimulation (blood transfusions, organ transplants, graftversus-host disease) and the immune disorder of the underlying disease itself are likely to be involved. The most important characteristics of these complications during the initial stages of their progression is their reversibility on withdrawal of the immunosuppressive agents. This justifies careful clinical and immunological monitoring of these patients.

The Mls locus on chromosome 1 controls the expression of cellular determinants that are responsible for stimulating mixed lymphocyte reactions between H-2-identical strains. However, the biochemical nature of Mls antigenic determinants remains undefined. It has been proposed that Ly-17 lymphoid cell surface antigens (also known as Ly.m.20.2 and LyM-1) and Mls antigens could be identical because they are both encoded by loci on chromosome 1 and display similar tissue distribution. The Ly-17 locus encodes polymorphic alleles of the IgG Fc receptor (Fc gamma R). In the present study, two approaches were used to address the question of whether Fc gamma R are involved in T cell recognition of Mls antigen. In the first approach we tested the effect of Fc gamma R blockade by heat-aggregated mouse IgG or anti-Fc gamma R monoclonal antibodies (2.4.G2) on the ability of an Ia+, Fc gamma R+ Mlsa-expressing B cell hybrid (LBB.3.4.16) to stimulate interleukin 2 secretion by an anti-Mlsa-specific T cell hybrid. We show that blockade of Fc gamma R does not inhibit the Mlsa-specific stimulation of T cells during a 24-h culture period in which Fc gamma R remain blocked. In the second approach, we derived irradiation-induced variants of LBB.3.4.16 to dissociate Fc gamma R expression and Mls antigen expression. We describe 2 LBB variants which no longer stimulate Mlsa-reactive T cells but do express Fc gamma R. Compared to parental LBB cells, the capacity of variant LBB cells to present soluble antigen to Ia-restricted T cells is unaffected. Collectively, these results indicate that Fc gamma R expression and Mlsa antigen stimulation can be dissociated. We conclude that Fc gamma R expression may be necessary, but not sufficient for T cell recognition of Mls antigen.

We have examined the biologic characteristics and immunologic properties of epidermal cell-derived lymphocyte differentiating factor (ELDIF), a lymphocyte differentiating factor produced by cultured human keratinocytes. The ELDIF was semipurified by a gel filtration procedure. This factor, which is distinct from prostaglandins, epidermal cell-derived thymocyte activating factor (ETAF), and the well-known thymic hormones (thymulin, thymopoietin, and thymosin alpha 1) did not exhibit any interleukin (IL)-1, IL-2, or IL-3 activity. It strongly inhibited in vitro lymphoproliferative responses of normal mouse spleen cells to phytohemagglutinin, concanavalin A, and lipopolysaccharide. This dose-dependent phenomenon was associated with a suppression of IL-2 production rather than any toxic effect. It can be concluded that ELDIF, a product of human epidermal cells, which displays in vitro T-cell differentiation and regulatory activities, could be of major importance in vivo in the control of cutaneous inflammatory reactions.

Mice deficient in the CD4 molecule (CD4-/-) are widely used to evaluate the requirement for CD4+ T cell help in viral, tumoral, and transplantation immunity. Previous studies, showing that CD4-/- mice develop impaired contact hypersensitivity (CHS) responses, have suggested that CD4+ T cells are required for the optimal induction of this skin inflammatory reaction. other studies have, however, demonstrated that CHS was mediated by CD8+ T cells, without the need for CD4+ T cell help. Here, we show that CD4-/- mice develop a normal delayed-type hypersensitivity response to protein antigen, which is mediated by major histocompatibility molecules class II-restricted CD4-CD8- T cells, but a decreased CHS response to 2,4-dinitro-fluorobenezene. Analysis of the hapten-specific T cell pool demonstrates that priming of CD8+ T cells occurred normally in CD4-/- mice, as assessed by specific proliferative responses and interferon-gamma (IFN-gamma) production of purified CD8+ T cells. Furthermore, CD8+ T cells were able to adoptively transfer a normal CHS reaction. In contrast, total lymph node cells from CD4-/- mice showed decreased IFN-gamma production and diminished specific cytotoxic T lymphocytes (CTL) activity, which could be reversed by in vitro restimulation with hapten-pulsed class II-deficient antigen-presenting cells. These data confirm that class I-restricted CD8+ T cells can fully develop in effectors of CHS in the absence of CD4+ T cell help and suggest that the impaired CHS in CD4-/- mice is because of the presence of a class II-restricted T cell subset, which controls CHS by inhibiting hapten-specific CTL responses.

Irritant contact dermatitis (ICD) is a frequent inflammatory skin disease induced by skin contact with low molecular weight chemicals such as haptens endowed with proinflammatory properties. Allergic contact dermatitis (ACD) is a frequent complication of ICD and is mediated by hapten-specific T cells primed in lymph nodes by skin emigrating dendritic cells. The aim of this study was to analyze the relationship between ICD and ACD to 2,4-dinitrofluorobenezene (DNFB) in C57BL/6 and BALB/C mice, which develop a severe and a moderate skin inflammation, respectively. Upon a single skin painting with DNFB, C57BL/6 developed within hours a more severe dose-dependent ICD response as compared to BALB/C mice, which was associated with enhanced upregulation of IL-1beta, IL-6, and IL-10. Skin exposure to a low dose of DNFB resulted, in both strains, in a low ICD that resolved in a few hours. Alternatively, skin painting with either an intermediate or a high DNFB concentration induced an ICD that subsequently gave rise to an ACD reaction whose intensity was proportional to the magnitude of the ICD response and was more severe in C57BL/6 mice than in BALB/C mice. In conclusion, the hapten-induced skin contact irritation conditions the development and the severity of ACD.

SummaryClonal lineage information is fundamental in revealing cell fate choices. Using genetic single-cell labeling in utero, we investigated lineage segregations during anteroposterior axis formation in mouse. We show that while endoderm and surface ectoderm segregate during gastrulation, neural ectoderm and mesoderm share a common progenitor persisting through all stages of axis elongation. These data challenge the paradigm that the three germ layers, formed by gastrulation, constitute the primary branchpoints in differentiation of the pluripotent epiblast toward tissue-specific precursors. Bipotent neuromesodermal progenitors show self-renewing characteristics and may represent the cellular substrate coupling sustained axial elongation and coordinated differentiation of these tissues. These findings have important implications for the interpretation of the phenotypic defects of several mouse mutants and the directed differentiation of embryonic stem (ES) cells in vitro.

International audience; From embryonal carcinoma cells labeled with fucose, two main classes of glycopeptide products of Pronase digestion can be distinguished by Sephadex G-50 column chromatography: one eluted near the excluded volume and a smaller one. The large fucosyl-glycopeptides are scarcely present in differentiated cells derived from embryonal carcinoma cells (i.e., fibroblastlike cells, myoblasts, and parietal yolk-sac carcinoma). During in vitro differentiation of embryonal carcinoma cells, these large glycopeptides disappear almost completely. The small glycopeptides were analyzed by paper electrophoresis, concanavalin A-Sepharose affinity chromatography, and digestion with an endoglycosidase. The major components of these glycopeptides from embryonal carcinoma cells appear to be different from complex glycopeptides known to occur in adult cells. The glycopeptide pattern of mouse preimplantation embryos resembles that of embryonal carcinoma cells. These results suggest that the carbohydrate profile changes fundamentally during early stages of mammalian development.

International audience; The Escherichia coli lacZ gene has been used as an indicator gene for the study of cell lineage in vivo. To adapt this marker for gene expression studies, a sequence encoding a modified beta-galactosidase and including the simian virus 40 large tumor nuclear location signal (nls-beta-Gal) has been introduced into vectors. In differentiated cells, multipotential cells, and embryos, the constructs led to the expression of an enzymatically active protein. Its location was examined by its beta-galactosidase activity or by using antibodies and electron microscopy. The results show that the nls-beta-Gal protein remains mainly located at the nuclear periphery (probably at the nuclear pores) but does not reach the nucleoplasm. It suggests that an interaction with the nuclear membrane is necessary but not sufficient for protein uptake into the nucleus. In multipotential cells, the expression of nuclear location signal LacZ (nls-LacZ) interferes neither with cell growth nor with differentiation. Using various lacZ constructs, the transcriptional activity of embryos was studied. At the two-cell stage, the promoters of the Rous sarcoma virus, simian virus 40, and the beta-actin gene are functional but the Moloney murine leukemia virus long terminal repeat is not. Thus, transcriptional specificity must already be present at the stage of activation of the embryonic genome.

TP5, a synthetic pentapeptide corresponding to thymopoietin 32–36, was administered alone to eight adult volunteer patients with sarcoidosis. A dose of 50 mg of TP5 was given iv, three times a week for 6 weeks, to three patients with erythema nodosum (EN) and bilateral hilar adenopathy, and to one patient with sarcoids of the skin; and for 12 weeks, to the other four patients with skin sarcoids. Before treatment and every 3 weeks thereafter clinical features; routine laboratory tests; tests for cellular immunity, humoral immunity, and auto immunity; IgE levels; and polymorphonuclear functions were recorded. EN disappeared in 3 weeks; hilar adenopathy improved or disappeared more slowly. Improvement of skin sarcoids was noted (lesions flattened or were cured). No side effects were observed. No evident changes in routine tests, humoral and auto immunity, IgE levels, and functions of polymorphonuclear leukocytes were observed. Cutaneous anergy to skin multiests was observed in seven patients before treatment, and was corrected with TP5 in six cases. In patients with low levels of peripheral blood T cells and suppressor T cells (as determined using specific monoclonal antibodies), a progressive normalization was obtained with TP5. These data support the efficacy of TP5 in sarcoidosis, although the action of the drug may be only temporary, as spontaneous remission may have occurred in this open trial of only eight cases.

In mammals the embryo itself is derived from a few founder cells (reviewed in Mintz, 1974) that are specified at an as yet undefined stage before gastrulation. From these progenitors, many distinct cell types develop during the next few days. Their probable number is far greater than the number of described histological cell types. When the embryo progenitor cells are determined the genome has been epigenetically modified. Indeed, the male and female pronuclei display different properties (reviewed in Solter, 1987) due to distinct imprinting that occurs during gametogenesis (McGrath and Solter, 1984; Surani et al., 1984; reviewed in Monk, 1988). Further modifications of the zygotic genome probably occur during the early stages of embryogenesis, probably initiated by interactions between the three partners present at fertilization: the female cytoplasm and the two pronuclei. The relative importance of epigenetic modifications of regions of the chromosomes (by epigenetic, we mean any stably inherited modification of the genetic material such as methylation or special kind of secondary or tertiary configuration of the chromatin) compared to the repertoire of trans modulators in the control of the set of genes expressed in a particular cell is not easy to evaluate. Current hypotheses on the basis of these restrictions of potency involve cell position, cell interaction, cell lineage and timing (reviewed in Pedersen, 1986). Therefore, analysis of gene expression in relation to these parameters is of great interest.

International audience; We demonstrate that individual cells infected with and expressing a recombinant retrovirus carrying the Escherichia coli beta-galactosidase gene (lacZ) can be viably stained, analyzed, sorted, and cloned by fluorescence-activated cell sorting based on the levels of lacZ expressed. To accomplish this we have devised a method to enzymatically generate and maintain fluorescence in live mammalian cells. Accumulation of fluorescent products in cells is linear with time, with a direct correlation of fluorescence to enzymatic activity. This technology for beta-galactosidase detection is more sensitive than other available cytochemical or biochemical methods. We have used this procedure to show that the expression of psi-2-MMuLVSVnlsLacZ in the T-cell lymphoma BW5147 and the B-cell hybridoma SP2/0 is not completely stable and that subclones selected by the fluorescence-activated cell sorter for low lacZ activity demonstrate distinctly lower average expression of LacZ. These findings indicate the utility of beta-galactosidase as a reporter molecule at the single-cell level for studies of gene regulation, including studies of promoter efficacy, enhancer activity, trans-acting factors, and other regulatory elements.

Electrical membrane properties of embryonal non-differentiated carcinoma cells which have been extensively used for the study of early mammalian embryogenesis were investigated by using patch clamp techniques. These multipotential cells were found to contain a restricted repertoire of a small number of ionic channels on the whole cell membrane. The most abundant type was a voltage- and calcium-activated potassium channel with characteristics similar to those described in fully differentiated cells.

International audience; Mouse embryonal carcinoma PCC4 cells are connected by extensive gap and tight junctions. When the cells are incubated in a medium containing Fab fragments against embryonal carcinoma F9 cells, they round up and a process of junctional removal is initiated. In particular, gap junctions are internalized and after 30 hr of incubation with the anti-F9 Fab fragments both tight and gap junctions are no longer present at the cell surface; however, the cells are still in contact by means of small attachment sites.

Publisher Summary This chapter describes methods necessary to (l) maintain stem cells in an undifferentiated state in culture, (2) induce the cells to differentiate under controlled conditions, (3) isolate new stem-cell lines directly from embryos, and (4) introduce genes by transfection or infection into embryonal carcinoma (EC) cells. Mouse teratocarcinomas are tumors that originate from the proliferation of a pluripotent stem cell, the EC cell. In addition to these stem cells, the tumors contain a variety of differentiated tissues that resemble those of the early embryo. EC cells have also been used to analyze the expression of gene regulatory elements in stem cells. In addition, EC cells have been used in a number of studies that are not strictly developmental. More recently, methods have been described to obtain stem-cell lines directly from early mouse embryos; these are called “EK cells.” Although very similar to EC cells, EK cells contribute much more readily to somatic tissues of chimaeric embryos following injection into blastocysts and can give rise to germ-line chimeras.

International audience; Metabolic cooperation has been used as an index of intercellular communication between mouse embryonal carcinoma (EC) and other cell types. EC cells do not cooperate with differentiated cells of various properties or origins. In contrast they cooperate with cells of all other EC lines tested, including a human teratocarcinoma line, but with different efficiencies. This might reflect differences either in cell-cell interactions or in the formation of gap junctions. During in vitro differentiation, EC cells appear to remain isolated from differentiated cell types.

International audience; Retroviral gene expression is inhibited in embryonal carcinoma (EC) cells. We have constructed a recombinant retroviral vector that is capable of expressing the neomycin-resistance (neo) gene in EC cells. The critical modification that permits expression of the neo gene is the insertion of a composite simian virus 40 early gene-herpes simplex virus type 1 thymidine kinase gene (SVtk) promoter 3' to the viral first intron and 5' to the neo gene. When the SVtk promoter is deleted, the recombinant retrovirus is either unable or extremely inefficient at expressing the neo gene in EC cells.

International audience; Two-cell and four-cell preimplantation mouse embryos were cocultured in vitro with fibroblasts producing the recombinant retrovirus M-MuLV-neo. No wildtype helper virus was detected in these cultures. Of the embryos that survived the in vitro cultivation and the reimplantation into foster mothers, 2 of 15 that were tested contained the proviral genome. The provirus integrated as a single copy at a unique site. We estimate that approximately equal to 20% of the cells in each of the two transgenic fetuses contained the provirus.

International audience; We show that a gene introduced into cells of mouse embryos by a retrovirus can serve as a heritable marker for the study of cell lineage in vivo. We constructed a defective recombinant retrovirus in which the Escherichia coli beta-galactosidase (lacZ) gene is inserted in the genome of a Muloney murine leukemia virus (M-MuLV). Expression of lacZ was detected with a histochemical stain that can be applied to cultured cells and embryonic tissue. Infection of cultured cells showed that lacZ has no detectable deleterious effects on cell viability or growth, that the enzyme is stably expressed in the progeny of infected cells for many generations in the absence of selective pressure, and that the virus can induce lacZ in a variety of cell types. Following injection of the virus into mid-gestation mouse embryos, clones of lacZ-positive cells were detected in skin, skull, meninges, brain, visceral yolk sac, and amnion. We identified the cell types comprising a series of lacZ-positive clones in the visceral yolk sac and skin to learn the lineage relationships of the labelled cells. In each tissue, we obtained evidence that several cell types have a pluripotential ancestor and that cell fate is progressively restricted as development proceeds.

Decouvertes il y a une vingtaine d'annees, les glycoproteines membranaires CD1 partagent, avec les produits classiques des genes du CMH, une similitude de structure et un role de presentation des antigenes a des lymphocytes T. La nature singuliere des antigenes presentes par les molecules CD1 et le mecanisme cellulaire conduisant a leur presentation font du systeme restreint par les molecules CD1 un systeme particulier, complementaire du systeme conventionnel sous le controle du CMH. Parallelement aux lymphocytes T CD1 restreints, il existe une population de lymphocytes T CD1 autoreactifs. Parmi ces derniers, certaines sous-populations conservees entre l'homme et la souris pourraient regler la reponse immunitaire contre les agents pathogenes, avoir une fonction antitumorale et controler certains phenomenes d'auto-immunite. Certaines de ces cellules autoreactives sont capables de reconnaitre des antigenes glycolipidiques et pourraient reconnaitre des glycolipides du soi presentes par CD1. Ce phenomene, qui semble dote d'une certaine specificite tissulaire, pourrait jouer un role dans le controle de l'homeostasie tissulaire.

L’eczéma allergique de contact est une dermatose inflammatoire fréquente, due à l’activation de lymphocytes T (LT) CD8+ cytotoxiques spécifiques d’haptènes en contact avec la peau. Les LT CD4+ sont, quant à eux, doués d’une fonction régulatrice et tolérogène, puisqu’ils limitent l’inflammation cutanée chez les patients (régulation) et préviennent le développement des LT effecteurs chez les individus sains (tolérance) : l’eczéma correspond donc à une rupture de la tolérance immunitaire aux haptènes présents dans l’environnement quotidien. Plusieurs sous-populations de LT CD4+ régulateurs (LT reg), parmi lesquelles celle des LT CD4+CD25+ naturels, sont impliquées dans la tolérance et la régulation de l’eczéma, via la production des cytokines immunosuppressives IL-10 (interleukine-10) et TGFβ (transforming growth factor β). Les travaux en cours ont pour objectif de ré-induire une tolérance immunitaire dans l’eczéma, soit en améliorant les méthodes existantes d’induction de tolérance aux haptènes (tolérance orale, tolérance à faibles doses, immunothérapie spécifique, tolérance induite par les rayons ultraviolets), soit en développant de nouvelles molécules capables d’activer les LT reg. Plus généralement, les données issues de ces travaux devraient pouvoir être appliquées au traitement des maladies auto-immunes ou allergiques, caractérisées par un déficit fonctionnel ou quantitatif en Ltreg à l’origine d’une rupture de la tolérance aux auto-antigènes ou aux allergènes de l’environnement., Allergic contact dermatitis (ACD) is a skin inflammatory disease mediated by activation of CD8+ cytotoxic T cells specific for haptens in contact with the skin. CD4+ T cells behave as both regulatory and tolerogenic cells since they down-regulate the skin inflammation in patients with ACD (regulation) and prevent the developement of eczema (tolerance) in normal individuals. Thus, ACD corresponds to a breakdown of immune tolerance to haptens in contact with the skin. Several regulatory CD4+ T cell subsets (Treg), especially CD4+CD25+ natural Treg cells, are involved in immunological tolerance and regulation to haptens through the production of the immunosuppressive cytokines IL-10 and TGF-β. Ongoing strategies to re-induce immune tolerance to haptens in patients with eczema include improvement of existing methods of tolerance induction (oral tolerance, low dose tolerance, allergen-specific immunotherapy, UV-induced tolerance) as well as development of new drugs able to activate IL-10 producing Treg cells in vivo. Ongoing and future progress in this area will open up new avenues for treatment of eczema and more generally autoimmune and allergic diseases resulting from a breakdown of tolerance to autoantigens and allergens, respectively.

Table of contents Poster walk 11: miscellaneous drug hypersensitivity 2 (P92–P94, P96–P101) P92 16 years of experience with proton pump inhibitors (PPIs) Javier Dionicio Elera, Cosmin Boteanu, Maria Aranzazu Jimenez Blanco, Rosario Gonzalez-Mendiola, Irene Carrasco García, Antonio Alvarez, Jose Julio Laguna Martinez P93 Allergy evaluation of quinolone induced adverse reactions Jaume Martí Garrido, Carla Torán Barona, Carolina Perales Chorda, Ramón López Salgueiro, Miguel Díaz Palacios, Dolores Hernández Fernández De Rojas P94 Bupropion-induced acute urticaria and angioedema, a case report Emre Ali Acar, Ayse Aktas, Aylin Türel Ermertcan, Peyker Temiz P96 Delayed type hypersensitivity and study of cross-reactivity between proton-pump inhibitors Chien-Yio Lin, Chung-Yee Rosaline Hui, Ya-Ching Chang, Chih-Hsun Yang, Wen-Hung Chung P97 Diagnostic work-up in suspected hypersensitivity to proton-pump inhibitors: looking at cross-reactivity Fabrícia Carolino, Diana Silva, Eunice Dias De Castro, Josefina R. Cernadas P98 Management of infusion-related hypersensitivity reactions to enzyme replacement therapy for lysosomal diseases Luis Felipe Ensina, Carolina Aranda, Ines Camelo Nunes, Alex Lacerda, Ana Maria Martins, Ekaterini Goudouris, Marcia Ribeiro, José Francisco Da Silva Franco, Leandra Queiroz, Dirceu Solé P99 Management of insulin allergy with continuous subcutaneous insulin infusion Ceyda Tunakan Dalgiç, Aytül Zerrin Sin, Fatma Düsünür Günsen, Gökten Bulut, Fatma Ömür Ardeniz, Okan Gülbahar, Emine Nihal Mete Gökmen, Ali Kokuludag P100 Off-label use of icatibant for management of serious angioedema associated with angiotensin inhibitors Ana M. Montoro De Francisco, Talía Mª De Vicente Jiménez, Adriana M. Mendoza Parra, Angella M. Burgos Pimentel, Amelia García Luque P101 Thiocolchicoside anaphylaxis: an unusual suspect? Luis Amaral, Fabricia Carolino, Leonor Carneiro Leão, Eunice Castro, Josefina Cernadas Poster walk 12: betalactam hypersensitivity (P102–P111) P102 A curious delayed reading: a case report of a β-lactam allergy in a child Nicole Pinto, Joana Belo, João Marques, Pedro Carreiro-Martins, Paula Leiria-Pinto P103 Betalactam-induced hypersensitivity: a 10-years’ experience Amel Chaabane, Haifa Ben Romdhane, Nadia Ben Fredj, Zohra Chadly, Naceur A. Boughattas, Karim Aouam P104 Cefazolin hypersensitivity: towards optimized diagnosis Astrid P. Uyttebroek, Chris H. Bridts, Antonino Romano, Didier G. Ebo, Vito Sabato P105 Clavulanic acid allergy: two cases report Anabela Lopes, Joana Cosme, Rita Aguiar, Tatiana Lourenço, Maria-João Paes, Amélia Spínola-Santos, Manuel Pereira-Barbosa P106 Diagnosis of betalactam allergy in an allergy department Cíntia Rito Cruz, Rute Pereira Dos Reis, Elza Tomaz, Ana Paula Pires, Filipe Inácio P107 Diagnostic work-up of 410 patients with suspicion of betalactam antibiotic hypersensitivity Filipe Benito-Garcia, Inês Mota, Magna Correia, Ângela Gaspar, Marta Chambel, Susana Piedade, Mário Morais-Almeida P108 Immediate selective hypersensitivity reactions to clavulanic acid Alla Nakonechna, Yurij Antipkin, Tetiana Umanets, Fernando Pineda, Francisca Arribas, Volodymyr Lapshyn P109 Prevalence and incidence of penicillin hypersensitivity reactions in Colombia Pablo Andrés Miranda, Bautista De La Cruz Hoyos P110 Selective sensitization to amoxicilin and clavulanic acid Jose Julio Laguna Martinez, Aranzazu Jimenez Blanco, Javier Dionicio Elera, Cosmin Boteanu, Rosario Gonzalez-Mendiola, Marta Del Pozo P111 Infliximab-specific T cells are detectable also in treated patients who have not developed anti-drug antibodies Alessandra Vultaggio, Francesca Nencini, Sara Pratesi, Andrea Matucci, Enrico Maggi Poster walk 13: biologicals, local anesthetics, others (P112–P118) P112 A case report of allergic immediate systemic reaction to adalimumab and certolizumab Ceyda Tunakan Dalgiç, Fatma Düsünür Günsen, Gökten Bulut, Fatma Ömür Ardeniz, Okan Gülbahar, Emine Nihal Mete Gökmen, Aytül Zerrin Sin, Ali Kokuludag P113 Allergy to local anesthetics: negative predictive value of skin tests Ivana Cegec, Danica Juricic Nahal, Viktorija Erdeljic Turk, Matea Radacic Aumiler, Ksenija Makar Ausperger, Iva Kraljickovic, Iveta Simic P114 Cutaneous adverse reactions of molecular targeted agents: a retrospective analysis in 150 patients in our department Yukie Yamaguchi, Tomoya Watanabe, Megumi Satoh, Tomohiko Tanegashima, Kayoko Oda, Hidefumi Wada, Michiko Aihara P115 Generalized paralysis induced by local lidocaine injection Jaechun Jason Lee, Jay Chol Choi, Hwa Young Lee P116 Hypersensitivity to local anaesthetics: a 10 year review Rosa-Anita Rodrigues Fernandes, Emília Faria, Joana Pita, Nuno Sousa, Carmelita Ribeiro, Isabel Carrapatoso, Ana Todo Bom P117 Local anaesthetics: a rare culprit in hypersensitivity reactions Ana Rodolfo, Eunice Dias-Castro, Josefina Cernadas P118 Stevens–Johnson syndrome in clinical practice: a variant of clinical course Marina Voronova Poster walk 14: RCM (P119–P128) P119 13 cases of severe anaphylactic reactions due to radiocontrast media Jaume Martí Garrido, Ramon Lopez Salgueiro, Diana Kury Valle, Verónica Pacheco Coronel, Carolina Perales Chordá, Dolores Hernandez Fernandez De Rojas P120 Anaphylactic shock after administration of iodinated contrast medium during cardiac catheterization Roselle Catherine Yu Madamba, Marta Ferrer, Maria Jose Goikoetxea, Carmen D’Amelio, Amalia Bernad, Olga Vega, Gabriel Gastaminza P121 Anaphylactic shock and cardiac arrest induced by gadolinium-based contrast agents Beatriz Pola Bibián, Marina Lluncor Salazar, Gemma Vilà Nadal, Ana María Fiandor Roman, Javier Dominguez Ortega, Miguel Gonzalez Muñoz, Santiago Quirce Gancedo, Maria Rosario Cabañas Moreno P122 Anaphylaxis to gadobenate and cross-reactivity to other gadolinium-based contrast agents in two patients Kathrin Scherer Hofmeier P123 Anaphylaxis to glatiramer acetate in a patient with multiple sclerosis Fabrícia Carolino, Vladyslava Barzylovych, Josefina R. Cernadas P124 Delayed hypersensitivity reaction to radiocontrast media Fabrícia Carolino, Diana Silva, Leonor Leão, Josefina R. Cernadas P125 Drug reaction with eosinophilia and systemic symptoms induced by iodixanol Gemma Vilà-Nadal, Beatriz Pola, Marina Lluncor, Ana Fiandor, Teresa Bellón, Javier Domínguez, Santiago Quirce P126 Electronic consultation support system for radiocontrast media hypersensitivity changes clinician’s behavior Min-Suk Yang, Sun-Sin Kim, Sae-Hoon Kim, Hye-Ryun Kang, Heung-Woo Park, Sang-Heon Cho, Kyung-Up Min, Yoon-Seok Chang P127 Hypersensitivity reactions to iodinated contrast media: skin testing and follow-up Danica Juricic Nahal, Ivana Cegec, Viktorija Erdeljic Turk, Iva Kraljickovic, Matea Radacic Aumiler, Ksenija Makar Ausperger, Iveta Simic P128 Would iodine allergy exist? Clémence Delahaye, Jenny Flabbee, Julie Waton, Olivia Bauvin, Annick Barbaud Poster walk 15: MPE/type 4 (P129–P137) P129 Delayed hypersensitivity cutaneous reactions: a case/control study from a tunisian database Karim Aouam, Najah Ben Fadhel, Zohra Chadly, Nadia Ben Fredj, Naceur A. Boughattas, Amel Chaabane P130 Delayed hypersensitivity reactions to cephalosporins: a review of seven cases Joana Cosme, Anabela Lopes, Amélia Spínola-Santos, Manuel Pereira-Barbosa P131 Diclofenac induced allergic contact dermatitis: case series of four patients Sandra Jerkovic Gulin, Anca Chiriac P132 Late-onset maculopapular rash to irbesartan Bárbara Kong Cardoso, Elza Tomaz, Regina Viseu, Filipe Inácio P133 Nonimmediate hypersensitivity reactions to betalactams: a retrospective analysis Ana Moreira, Susana Cadinha, Ana Castro Neves, Patricia Barreira, Daniela Malheiro, J. P. Moreira Da Silva P134 Occupational airborne contact dermatitis to omeprazole Ružica Jurakic-Toncic, Suzana Ljubojevic, Petra Turcic P135 Ornidazole-induced fixed drug eruption confirmed by positive patch test on a residual pigmented lesion Liesbeth Gilissen, Sara Huygens, An Goossens P136 Repeated delayed reaction induced by amoxicillin and amoxicillin clavulanate Inmaculada Andreu, Ramon Lopez-Salgueiro, Alicia Martinez Romero, Pau Gomez Cabezas P137 Systemic photosensitivity from fenofibrate in a patient photo-sensitized to ketoprofen Liesbeth Gilissen, An Goossens Poster walk 16: HLA genetics (P138–P146) P138 A copy number variation in ALOX5 and PTGER1 is associated with nonsteroidal anti-inflammatory drugs induced urticaria and/or angioedema Pedro Ayuso Parejo, Maria Del Carmen Plaza-Serón, Inmaculada Doña, Natalia Blanca López, Carlos Flores, Luisa Galindo, Ana Molina, James Richard Perkins, Jose Antonio Cornejo-García, José Augusto García-Agúndez, Elena García-Martín, Paloma Campo, María Gabriela Canto, Miguel Blanca P139 Association of galectin-3 (LGALS3) single nucleotide polymorphisms with non-steroidal anti-inflammatory drugs-induced urticaria/angioedema José Antonio Cornejo-Garcia, Inmaculada Doña, Rosa María Guéant-Rodríguez, Natalia Blanca-López, María Carmen Plaza-Serón, Raquel Jurado-Escobar, Esther Barrionuevo, María Salas, María Luisa Galindo, Gabriela Canto, Miguel Blanca, Jean-Louis Guéant P140 Detection of T cell responses to ticlopidine using peripheral blood mononuclear cells from HLA-A*33:03+ healthy donors Toru Usui, Arun Tailor, Lee Faulkner, John Farrell, Ana Alfirevic, B. Kevin Park, Dean J. Naisbitt P141 Epistasis approaches to identify novel genes potentially involved in NSAIDs hypersensitivity James Richard Perkins, Jose Antonio Cornejo García, Oswaldo Trelles, Inmaculada Doña, Esther Barrionuevo, María Salas, María Auxiliadora Guerrero, Miguel Blanca, Alex Upton P142 Genetic predisposition of cold medicine related SJS/TEN with severe ocular complications Mayumi Ueta, Hiromi Sawai, Chie Sotozono, Katushi Tokunaga, Shigeru Kinoshita P143 HLA-B*13:01 and dapsone induced hypersensitivity in Thai population Chonlaphat Chonlaphat Sukasem, Patompong Satapornpong, Therdpong Tempark, Pawinee Rerknimitr, Kulprapat Pairayayutakul, Jettanong Klaewsongkram P144 HLA-B*15:02 alleles and lamotrigine-induced cutaneous adverse drug reactions in Thai Chonlaphat Sukasem, N. Koomdee, T. Jantararoungtong, S. Santon, A. Puangpetch, U. Intusoma, W. Tassaneeyakul, V. Theeramoke P145 HLA-B*38:01 and HLA-A*24:02 allele frequencies in Spanish patients with lamotrigine-induced SCARs Teresa Bellón, Elena Ramirez, Alberto Manuel Borobia, Hoi Tong, Jose Luis Castañer, Francisco José De Abajo P146 Overrepresentation of a class II HLA haplotype in severe hypersensitivity type I reactions to carboplatin Violeta Régnier Galvao, Rebecca Pavlos, Elizabeth Mckinnon, Kristina Williams, Alicia Beeghly-Fadiel, Alec Redwood, Elizabeth Phillips, Mariana Castells Poster walk 17: in vivo diagnosis + sIgE (P147–P154) P147 Absence of specific Ig-e against beta-lactams 9 months after an allergic reaction to amoxicillin-clavulanic acid Elisa Boni, Marina Russello, Marina Mauro P148 Drug provocation tests in suspected opioid allergy Kok Loong Ue, Krzysztof Rutkowski P149 Improvement to the specific IgE cut-off in the assess of β-lactamic allergy Victor Soriano Gomis, Jorge Frances Ferre, Angel Esteban Rodriguez, Vicente Cantó Reig, Javier Fernandez Sanchez P150 Initial false negative specific IgE to gelatin in a patient with gelatin-induced anaphylaxis Christine Breynaert, Erna Van Hoeyveld, Rik Schrijvers P151 Inmediate reactions to beta-lactam antibiotics: pattern of skin test response over the time Jose Julio Laguna Martinez, Rosario Gonzalez Mendiola, Javier Dionicio Elera, Cosmin Boteanu, Aranzazu Jimenez Blanco, Marta Del Pozo, Raquel Fuentes Irigoyen P152 New fluorescent dendrimeric antigens for the evaluation of dendritic cell maturation as a test to detect allergy reactions to amoxicillin Daniel Collado, Yolanda Vida, Francisco Najera, Ezequiel Perez-Inestrosa, Pablo Mesa-Antunez, Cristobalina Mayorga, María José Torres, Miguel Blanca P153 Positive skin test or positive specific IgE to penicillin does not predict penicillin allergy Line K. Tannert, Charlotte G. Mortz, Per Stahl Skov, Carsten Bindslev-Jensen P154 Significance of skin testing and in vitro-analysis of neuromuscular blocking agents in diagnosis of perioperative drug hypersensitivity: evaluation of a negative control population Wolfgang Pfützner, Hannah Dörnbach, Johanna Visse, Michele Rauber, Christian Möbs Poster walk 18: in vitro/ex vivo (P155–P158, P160–P164) P155 Diagnostic value of the lymphocyte toxicity assay (LTA) and the in vitro platelet toxicity assay (IPTA) for β-lactam allergy Abdelbaset A. Elzagallaai, Lindsey Chow, Awatif M. Abuzgaia, Michael J. Rieder P156 Enzyme linked immunospot assay used in the diagnosis of severe cutaneous adverse reactions to antimicrobials Alec Redwood, Jason Trubiano, Rebecca Pavlos, Emily Woolnough, Kaija Stautins, Christina Cheng, Elizabeth Phillips P157 Evaluation of in vitro diagnostic methods for identifying the culprit drugs in drug hypersensitivity Kenichi Kato, Hiroaki Azukizawa, Takaaki Hanafusa, Ichiro Katayama P158 Ex-vivo expanded skin-infiltrating T cells from severe drug eruptions are reactive with causative drugs: a possible novel method for determination of causative drugs Toshiharu Fujiyama, Hideo Hashizume, Takatsune Umayahara, Taisuke Ito, Yoshiki Tokura P160 In vitro release of IL-2, IL-5 and IL-13 in diagnosis of patients with delayed-type nickel hypersensitivity Mira Silar, Mihaela Zidarn, Helena Rupnik, Peter Korosec P161 Single cell analysis of drug responsive T cells; identification of candidate drug reactive T cell receptors in abacavir and carbamazepine hypersensitivity Alec James Redwood, Kaija Strautins, Katie White, Abha Chopra, Katherine Konvinse, Shay Leary, Rebecca Pavlos, Simon Mallal, Elizabeth Phillips P162 Specificity and sensitivity of LTT in DRESS: analysis of agreement with the Spanish pharmacovigilance system probability algorithm Rosario Cabañas, Elena Ramirez, Ana María Fiandor, Teresa Bellón P163 The role of interleukin-22 in β-lactam hypersensitivity Andrew Sullivan, Paul Whitaker, Daniel Peckham, B. Kevin Park, Dean J. Naisbitt P164 Vancomycin-specific T cell responses and teicoplanin cross-reactivity Wei Yann Haw, Marta E. Polak, Carolann Mcguire, Michael R. Ardern-Jones Poster walk 19: BAT and biomarkers (P165–P173) P165 A combination of early biomarkers useful for the prediction of severe ADRs Yumi Aoyama, Tetsuo Shiohara P166 Basophil activation test in the diagnostic approach of reactions during general anaesthesia Ana Moreira, Susana Cadinha, Patrícia Barreira, Ana Castro Neves, Daniela Malheiro, Sara Correia, J. P. Moreira Da Silva P167 IL-10 can be related to successful desensitization Asli Gelincik, Semra Demir, Fatma Sen, Hamza Ugur Bozbey, Muge Olgac, Derya Unal, Raif Coskun, Bahauddin Colakoglu, Suna Buyuozturk, Esin Çatin-Aktas, Gunnur Deniz P168 Immediate reactions to proton pump inhibitors: value of basophil activation test Maria Salas, Jose Julio Laguna, Esther Barrionuevo, J. Dionicio, Tahia Fernandez, R. Gonzalez-Mendiola, I. Olazabal, Maria Dolores Ruiz, Miguel Blanca, Cristobalina Mayorga, Maria José Torres P169 Improvement of the elevated tryptase criterion to discriminate IgE from non-IgE mediated allergic reactions Gabriel Gastaminza, Alberto Lafuente, Carmen D’Amelio, Amalia Bernad, Olga Vega, Roselle Catherine Madamba, M. Jose Goikoetxea, Marta Ferrer, Jorge Núñez P170 Low expression of Tim-3 could serve as a biomarker for control and diagnose maculopapular exanthema induced by drugs Tahia Diana Fernández, Inmaculada Doña, Francisca Palomares, Rubén Fernández, Maria Salas, Esther Barrionuevo, Maria Isabel Sanchez, Miguel Blanca, Maria José Torres, Cristobalina Mayorga P171 Role of basophil activation test using two different activation markers for the diagnosis of allergy to fluoroquinolones Esther Barrionuevo, Tahía Fernandez, Arturo Ruiz, Adriana Ariza, Maria Salas, Inmaculada Doña, Ana Molina, Miguel Blanca, Maria Jose Torres, Cristobalina Mayorga P172 The importance of basophil activation test in anaphylaxis due to celecoxib Amalia Bernad Alonso, Carmen D’Amelio Garófalo, Olga Vega Matute, Marta Ferrer Puga, María José Goikoetxea Lapresa, Roselle Catherine Yu Madamba, Gabriel Gastaminza Lasarte P173 The role of basophil activation test in the diagnosis of immediate type drug hypersensitivity to betalactam antibiotics Antonia Thinnes, Hans F. Merk, Jens Malte Baron, Martin Leverkus, Galina Balakirski Poster walk 20: TCR recognition, cellular (P174–P183) P174 Characterisation of the effect of co-inhibitory signalling on the activation of drug-derived antigen-specific T-cells Andrew Gibson, Monday Ogese, Lee Faulkner, B. Kevin Park, Dean J. Naisbitt P175 Characterization of drug hapten-specific T cell responses in piperacillin hypersensitive patients Zaid Al-Attar, Fiazia Yaseen, Xiaoli Meng, Rozalind Jenkins, Paul Whitaker, Daniel Peckham, Lee Faulkner, John Farrel, Kevin Park, Dean Naisbitt P176 Characterization of the response of T-cells to telaprevir and its metabolite in normal volunteers Zaid Al-Attar, Khetam Alhilali, Yanni Xue, John Farrell, Lee Faulkner, Kevin Park, Dean Naisbitt P177 Characterization of the T cell receptor signatures of drug-responsive T cells Patricia Illing, Nicole Mifsud, Heidi Fettke, Jeffrey Lai, Rebecca Ho, Patrick Kwan, Anthony Purcell P178 Defining the signals between hepatocytes and immune cells in idiosyncratic drug-induced liver injury (DILI) Monday O. Ogese, Lee Faulkner, B. Kevin Park, Catherine Betts, Dean J. Naisbitt P179 Development of novel chemicals that do not bind to HLA-B*57:01 or activate CD8 + T-cells through modification of the 6-amino cyclopropyl group of abacavir Paul Thomson, John Farrell, Mohammad Alhaidari, Neill Berry, Paul M. O’Neill, B. Kevin Park, Dean J. Naisbitt P180 Generation and characterization of dapsone- and nitroso-dapsone-specific T-cell clones using lymphocytes from healthy volunteers Abdulaziz Alzahrani, Monday O. Ogese, John Farrell, Lee Faulkner, Andrew Gibson, Arun Tailor, B. Kevin Park, Dean J. Naisbitt P181 Identification of benzylpenicillin-hapten peptides responsible for naïve T-cell activation and immunization of allergic patients to penicillin Marie Eliane Azoury, Lucia Fili, Rami Bechara, Noémie Scornet, Cathy Nhim, Richard Weaver, Nancy Claude, Delphine Joseph, Bernard Maillere, Paola Parronchi, Marc Pallardy P182 Massive expansion of clonotypic and polycytotoxic CD8+ T cells in toxic epidermal necrolysis Axel Patrice Villani, Aurore Rozières, Benoît Bensaïd, Mathilde Tardieu, Floriane Albert, Virginie Mutez, Tugba Baysal, Marc Pallardy, Janet Maryanski, Jean-François Nicolas, Osami Kanagawa, Marc Vocanson P183 Pharmaco-immunological synapse of HLA-drug-TCR in SCAR Shuen-Iu Hung Poster walk 21: new in vitro methods, haptens, etc. (P184–P194) P184 Amoxicillin-clavulanate forms distinct multiple haptenic structures on human serum albumin in patients Xiaoli Meng, Arun Tailor, Caroline J. Harrison, Rosalind E. Jenkins, Paul Whitaker, Neil S. French, Dean J. Naisbitt, B. Kevin Park P185 Dendrimeric antigens for studying the influence of penicillin determinants orientation on IgE recognition Maria Isabel Montañez, Cristobalina Mayorga, Francisco Najera, Adriana Ariza, Tahia D. Fernandez, Maria Salas, Angela Martin-Serrano, Miguel Blanca, Ezequiel Perez-Inestrosa, Maria Jose Torres P186 Dendrimeric antigens on solid supports: designed materials for IgE quantification Yolanda Vida, Maria Isabel Montañez, Noemi Molina, Daniel Collado, Francisco Najera, Adriana Ariza, Maria Jose Torres, Cristobalina Mayorga, Ezequiel Perez-Inestrosa P187 Development of a screening assay for drug hypersensitivity using naïve T cells from donors with seven different HLA class I risk alleles Lee Faulkner, Sally Wood, Ana Alfirevic, Munir Pirmohamed, Dean J. Naisbitt, B. Kevin Park P188 Different patterns of recognition of structures derived from amoxicillin by IgE antibodies from patients with immediate hypersensitivity reactions to betalactams Adriana Ariza, Cristobalina Mayorga, María Isabel Montañez, María Salas, Inmaculada Doña, Ángela Martín-Serrano, Ezequiel Pérez-Inestrosa, Dolores Pérez-Sala, Miguel Blanca, Antonio E. Guzmán, María José Torres P189 High-resolution typing of HLA polymorphism and T-cell receptor repertoire for severe adverse drug reactions based on the cost-effective next-generation sequencing approaches Tai-Ming Ko, Yuan-Tsong Chen, Jer-Yuarn Wu P190 Identification and fate of intracellular proteins haptenated by amoxicillin Francisco J. Sánchez-Gómez, Juan M. González-Morena, Yolanda Vida, Ezequiel Pérez-Inestrosa, Miguel Blanca, María J. Torres, Dolores Pérez-Sala P191 In vitro detection of terbinafine protein adducts Arun Tailor, Toru Usui, Yanni Xue, Xiaoli Meng, Dean J. Naisbitt, B. Kevin Park P192 MicroRNAs dysregulation in PBMCs from drug hypersensitivity patients during drug challenge in vitro Alejandra Monroy Arreola, Jesus Agustin Badillo Corona, Silvia Mendez Flores, Judith Dominguez Cherit, Dean J. Naisbitt, Noe Valentin Duran Figueroa, Jose Luis Castrejon Flores P193 NSAIDs-exacerbated cutaneous disease: high throughput gene expression profiling José Antonio Cornejo-García, James Perkins, Natalia Blanca-López, Diana Pérez-Alzate, Raquel Jurado-Escobar, Inmaculada Doña, Gador Bogas, María J. Torres, Gabriela Canto, Miguel Blanca P194 Utility of skin tests in non-immediate reactions to amoxicillin Luis Mario Tubella Marti, Fernando Pineda De La Losa, Francisca Arribas Poves, Jaime Tubella Lopez, Teodora Lopez Santiago

Food allergy is a major public health which impacts patients’ quality of life and can cause life-threatening allergic symptoms upon allergen ingestion. Currently, there is no efficacious treatment apart from allergen eviction. In that context, epicutaneous allergen immunotherapy (EPIT) is a potential treatment still in development which aims at re-inducing tolerance (desensitization) in allergic patients through repeated epicutaneous allergen application. Immune mechanisms underlying EPIT efficacy are poorly understood but imply the induction of regulatory T lymphocytes (TREG) and an immune deviation. Thus, my thesis project aimed at (1) identifying the skin dendritic cell (skDC) subsets responsible for EPIT efficacy, and (2) determining which skDC acquire tolerogenic phenotype and functions throughout EPIT treatment. Taking advantage of preclinical mouse models, we demonstrated the requirement of epidermal Langerhans cells (LC) for EPIT efficacy contrary to conventional dermal type 1 DC (cDC1). Besides, the longitudinal monitoring of DC revealed a modulation of their activation status with EPIT. Functionally, after EPIT, LC activated more preferentially TREG at the detriment of TEFF, while cDC2 skewed type 2 T cell response toward type 1 and type 17 profile that may benefit to EPIT-induced desensitization. Those results open new avenues for the development of predictive biomarkers, strategies for improvement and future efficacious personalized medicine; L’allergie alimentaire est un problème majeur de santé publique qui affecte grandement la qualité de vie des patients, principalement des enfants, et peut causer des symptômes sévères voire mortels, lors de l’ingestion de faibles quantités d’un allergène. A l’heure actuelle, le seul traitement efficace est l’éviction de l’allergène. Dans ce contexte, l’immunothérapie allergénique épicutanée (EPIT) est un traitement potentiel qui vise à réinduire une tolérance (désensibilisation) chez les patients allergiques via l’administration répétée sur la peau de l’allergène responsable. Les mécanismes immunitaires sous-jacents à l’efficacité de l’EPIT restent mal compris mais dépendent notamment de l’induction de lymphocytes T régulateurs (LTREG) et d’une déviation immunitaire. Ainsi, mon projet de thèse avait pour objectif d’identifier (1) les populations de cellules dendritiques (DC) cutanées qui conditionnent l’efficacité du traitement, et (2) déterminer quelles DC cutanées acquièrent un phénotype et une fonction tolérogénique au fur et à mesure du traitement. A l’aide de modèles pré-cliniques d’allergie, mes travaux de recherche ont permis d’identifier les cellules de Langerhans (LC) épidermiques comme nécessaires à l’efficacité du traitement, contrairement aux cellules dendritiques conventionnelles de type 1 (cDC1) dermiques. En outre, l’étude longitudinale du phénotype et des fonctions des DC a mis en évidence que leur état d’activation était modulé avec EPIT. Fonctionnellement, après EPIT, les LC activent préférentiellement des LTREG au détriment des LTEFF., tandis que les cDC2 réorientent la réponse lymphocytaire de type 2 (Th2) vers une réponse type 1 et type 17. Ces résultats ouvrent la voie au développement de biomarqueurs d’efficacité et à des stratégies d’amélioration du traitement pour une médecine personnalisée et plus efficace