Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Stefan Chilmonczyk is active.

Publication


Featured researches published by Stefan Chilmonczyk.


Journal of Immunology | 2006

Phenotypic and Functional Similarity of Gut Intraepithelial and Systemic T Cells in a Teleost Fish

David Bernard; Adrien Six; Lionel Rigottier-Gois; Sébastien Messiaen; Stefan Chilmonczyk; Edwige Quillet; Pierre Boudinot; Abdenour Benmansour

Gut-associated lymphocytes were described in fish, but their involvement in immune responses is still unknown. In rainbow trout, intraepithelial lymphocytes (IELs) are scattered between gut epithelial cells, but neither Peyer’s patches nor mesenteric lymph nodes were identified. Rainbow trout IELs contain mainly T cells, because they expressed transcripts of T cell marker homologs of CD8, CD4, CD28, CD3ε, TCRζ, TCRγ, and TCRβ and lacked IgM. However, trout IELs did not show specific homing to the gut mucosa, which in mammals defines IELs as a distinctive mucosal population. A detailed analysis of the TCRβ repertoire of rainbow trout IELs was performed in both naive and virus-infected animals. TCRβ transcripts of rainbow trout IELs were highly diverse and polyclonal in adult naive individuals, in sharp contrast with the restricted diversity of IEL oligoclonal repertoires described in birds and mammals. Significant modifications of the trout IEL TCRβ repertoire were observed after a systemic infection with a fish rhabdovirus and were especially marked for Vβ4-bearing receptors as previously reported for spleen cells. Thus, we could not find any specific properties of the trout IEL TCRβ repertoire compared with the spleen and pronephros TCRβ repertoire, which questions the reality of a distinct IEL compartment in teleosts. Our findings suggest that a highly diversified αβ ΤCR repertoire is maintained in fish IELs in the absence of Peyer’s patches and mesenteric lymph nodes, whereas the restricted diversity of mouse αβ IELs is attributed to multiple cycles of activation and recirculation, allowing a progressive narrowing of the repertoire.


Journal of Virology | 2000

Rainbow Trout Sleeping Disease Virus Is an Atypical Alphavirus

Stéphane Villoing; Monique Béarzotti; Stefan Chilmonczyk; Jeannette Castric; Michel Brémont

ABSTRACT Sleeping disease (SD) is currently a matter of concern for salmonid fish farmers in most parts of the world. A viral etiology of SD has recently been suspected, since virus-like particles have been observed in infected rainbow trout cells. In salmonid-derived cell lines, the maximal rate of virus production was observed at 10°C, while little virus was produced at 14°C. Through biochemical, physicochemical, and morphological studies, SD virus (SDV) was shown to be an enveloped virus of roughly 60 nm in diameter. The genome consists of 12 kb of RNA, with the appearance of a 26S subgenomic RNA during the time course of SDV replication. The screening of a random-primed cDNA library constructed from the genomic RNA of semipurified virions facilitated the identification of a specific SDV cDNA clone having an open reading frame related to the alphavirus E2 glycoproteins. To extend the comparison between SDV structural proteins and the alphavirus protein counterparts, the nucleotide sequence of the total 4.1-kb subgenomic RNA has been determined. The 26S RNA encodes a 1,324-amino-acid polyprotein exhibiting typical alphavirus structural protein organization. SDV structural proteins showed several remarkable features compared to other alphaviruses: (i) unusually large individual proteins, (ii) very low homology (ranging from 30 to 34%) (iii) an unglycosylated E3 protein, and (iv) and E1 fusion domain sharing mutations implicated in the pH threshold. Although phylogenetically related to the Semliki Forest virus group of alphaviruses, SDV should be considered an atypical member, able to naturally replicate in lower vertebrates.


International Journal of Food Microbiology | 2010

Intragastric administration of a superoxide dismutase-producing recombinant Lactobacillus casei BL23 strain attenuates DSS colitis in mice

Laurie Watterlot; Tatiana Rochat; Harry Sokol; Claire Cherbuy; Ismael Bouloufa; François Lefèvre; Jean-Jacques Gratadoux; Edith Honvo-Hueto; Stefan Chilmonczyk; Sébastien Blugeon; Gérard Corthier; Philippe Langella; Luis G. Bermúdez-Humarán

Human immune cells release large amounts of reactive oxygen species (ROS) such as superoxide radical and hydrogen peroxide via respiratory burst. In inflammatory bowel diseases, a sustained and abnormal activation of the immune response results in oxidative stress of the digestive tract and in a loss of intestinal homeostasis. We previously reported that heterologous production of the Lactobacillus plantarum manganese catalase (MnKat) enhances the survival of Lb. casei BL23 when exposed to oxidative stress. Anti-inflammatory effects were observed after Lb. casei BL23 oral administrations in moderate murine dextran sodium sulfate (DSS)-induced colitis, without added effects of the MnKat production. Here, we evaluated the protective effects obtained by an improved antioxidative strategy. The Lactococcus lactis sodA gene was expressed in Lb. casei BL23 which acquired an efficient manganese superoxide dismutase (MnSOD) activity. The effects of Lb. casei MnSOD alone or in combination with Lb. casei MnKat were compared first in eukaryotic cell PMA-induced oxidative stress model and then in severe murine DSS-induced colitis. Based on ROS production assays as well as colonic histological scores, a significant reduction of both oxidative stress and inflammation was observed with Lb. casei MnSOD either alone or in combination with Lb. casei MnKat. No added effect of the presence of Lb. casei MnKat was observed. These results suggest that Lb. casei BL23 MnSOD could have anti-inflammatory effects on gut inflammation.


Infection and Immunity | 2003

Trojan horse effect: phagocyte-mediated Streptococcus iniae infection of fish.

Amir Zlotkin; Stefan Chilmonczyk; Marina Eyngor; Avshalom Hurvitz; Claudio Ghittino; Avi Eldar

ABSTRACT The salmonid macrophage-like cell line RTS-11 and purified trout pronephros phagocytes were used to analyze in vitro entry and survival of two Streptococcus iniae serotypes. Efficient invasion by S. iniae occurred in both cells, but only the type II strain persisted in pronephros phagocytes for at least 48 h. Ex vivo models of opsonin-dependent phagocytosis by pronephros phagocytes demonstrated increased phagocytosis efficacy. Analysis of phagocytes collected from diseased fish demonstrated that ∼70% of the bacteria contained in the blood during the septic phase of the disease were located within phagocytes, suggesting an in vivo intracellular lifestyle. In addition to the augmented levels of bacteremia and enhanced survival within phagocytes, S. iniae type II induces considerable apoptosis of phagocytes. These variabilities in intramacrophage lifestyle might explain differences in the outcomes of infections caused by different serotypes. The generalized septic disease associated with serotype II strains is linked not only to the ability to enter and multiply within macrophages but also to the ability to cause considerable death of macrophages via apoptotic processes, leading to a highly virulent infection. We assume that the phenomenon of survival within phagocytes coupled to their apoptosis plays a crucial role in S. iniae infection. In addition, it may provide the pathogen an efficient mechanism of translocation into the central nervous system.


Annual Review of Fish Diseases | 1992

The thymus in fish: Development and possible function in the immune response

Stefan Chilmonczyk

Abstract With the exception of Agnatha, fish possess the functional equivalent of the thymus gland found in higher vertebrates. As in other vertebrates, this gland originates from the pharyngeal pouches and ontogenically is the first lymphoid organ to be infiltrated with lymphoid cells. Histology of the structure may differ from one species to another but the cellular component is basically similar. The (paired) gland is surrounded by an epithelial capsule. Within the gland a framework of reticulo-epithelial cells supports the lymphocytes. The age-related involution process, which characterizes the thymus of higher vertebrates, does not necessarily occur in fish. Nevertheless, thymus growth and function may be modulated by those factors that induce its involution such as aging, season, sexual maturity, and stress. The major role played by the thymus in the immune response of higher vertebrates is presumed to occur in fish. Thymus-derived cell dependent immune reactions have been demonstrated in fish. The cells that mediate these functions are designated as T-like cells. So far, cell surface markers equivalent to those of mammalian T lymphocytes have not been characterized. The T lymphocyte specificities are supposed to be acquired within or via the thymic microenvironment. Unfortunately, there is limited data concerned with the cytological and physiological basis of the maturation of thymus-derived cells. Direct involvement of the fish thymus in defense mechanisms has not been investigated extensively. The gland appears to be weakly protected because of its superficial location and is easily exposed to pathogens. Neoplasia is the main pathologic condition reported in the thymus of fish, with little else having been published regarding thymic pathology.


Applied and Environmental Microbiology | 2004

Clonality and Diversity of the Fish Pathogen Lactococcus garvieae in Mediterranean Countries

Marina Eyngor; Amir Zlotkin; Claudio Ghittino; Marino Prearo; Diane-Gaëlle Douet; Stefan Chilmonczyk; Avi Eldar

ABSTRACT Infection with Lactococcus garvieae is considered the most important risk factor for the European trout industry, and the losses are approximately 50% of the total production. To improve our understanding of the genetic links among strains originating from different countries, we examined the population structure of L. garvieae by comparing 81 strains isolated from different sources and ecosystems (41 farms in six countries) in which the bacterium is commonly found. Genetic similarities (as assessed with molecular tools, including restriction fragment length polymorphism ribotyping with two endonucleases) were compared with serological data. The combined results reveal that in endemic sites the bacterial population displays a clonal structure, whereas bacterial diversity characterizes sites where the infection is sporadic.


Journal of Immunology | 2008

Plasmacytoid Dendritic Cells Migrate in Afferent Skin Lymph

Florentia Pascale; Vanessa Contreras; Michel Bonneau; Alexandre Courbet; Stefan Chilmonczyk; Claudia Bevilacqua; Mathieu Eparaud; Violeta Niborski; Sabine Riffault; Anne-Marie Balazuc; Eliane Foulon; Laurence Guzylack-Piriou; Béatrice Riteau; Jayne Hope; Nicolas Bertho; Bernard Charley; Isabelle Schwartz-Cornil

Conventional dendritic cells enter lymph nodes by migrating from peripheral tissues via the lymphatic route, whereas plasmacytoid dendritic cells (pDC), also called IFN-producing cells (IPC), are described to gain nodes from blood via the high endothelial venules. We demonstrate here that IPC/pDC migrate in the afferent lymph of two large mammals. In sheep, injection of type A CpG oligodinucleotide (ODN) induced lymph cells to produce type I IFN. Furthermore, low-density lymph cells collected at steady state produced type I IFN after stimulation with type A CpG ODN and enveloped viruses. Sheep lymph IPC were found within a minor B(neg)CD11c(neg) subset expressing CD45RB. They presented a plasmacytoid morphology, expressed high levels of TLR-7, TLR-9, and IFN regulatory factor 7 mRNA, induced IFN-gamma production in allogeneic CD4(pos) T cells, and differentiated into dendritic cell-like cells under viral stimulation, thus fulfilling criteria of bona fide pDC. In mini-pig, a CD4(pos)SIRP(pos) subset in afferent lymph cells, corresponding to pDC homologs, produced type I IFN after type A CpG-ODN triggering. Thus, pDC can link innate and acquired immunity by migrating from tissue to draining node via lymph, similarly to conventional dendritic cells.


Developmental and Comparative Immunology | 1982

Rainbow trout lymphoid organs: cellular effects of corticosteroids and anti-thymocyte serum.

Stefan Chilmonczyk

Cellular populations were studied in lymphoid organs of rainbow trout. Kidney appeared to be the most important organ by the number of cells harvested. A high percentage of peroxidase positive cells was measured in kidney, spleen and blood. The use of cortisone and rabbit anti-thymocyte serum showed differences in ratio of sensitive cells from different organs. In fish treated with steroids, cell depletion was verified in each organ but histologic lesions were observed only in thymus. Rabbit anti-thymocyte serum was cytotoxic for the quasi-totality of thymocytes while it destroyed only a part of kidney, spleen and blood cells. No correlations could be made between steroid sensitive cells and anti-thymocyte serum sensitive cells.


Journal of Eukaryotic Microbiology | 1996

Comparative Development of Two Microsporidian Species: Enterocytozoon bieneusi and Enterocytozoon salmonis, Reported in AIDS Patients and Salmonid Fish, Respectively

Isabelle Desportes-Livage; Stefan Chilmonczyk; Ronald P. Hedrick; Cécile Ombrouck; Danielle Monge; Ibrahim Maiga; Marc Gentilini

ABSTRACT. Enterocytozoon bieneusi and Enterocytozoon salmonis are reported in HIV‐infected patients and in salmonid fish, respectively. Both species share the early development of the extrusion apparatus of the spores, which is completed prior to fission of the sporogonic syncytium into sporoblasts, and the early synthesis of polar tube constituents, but they differ in other developmental and sporogenetic processes. Enterocytozoon bieneusi develops in direct contact with the cytoplasm of epithelial cells whereas E. salmonis occurs only in the nucleus of leucocytes and epithelioid cells. Sporogonic nuclei, which are scattered throughout the sporont in E. bieneusi, are located in the periphery in E. salmonis. The multilamellar structures associated with the nuclear envelopes and the endoplasmic reticulum cisternae are specific for E. bieneusi. Additionally, the evolution of the polar tube precursors proceeds differently in the two parasites. In E. bieneusi, they transform into electron‐dense bodies associated with a reticulum and polar tubes derive from these structures according to a process similar to that reported in other microsporidia. In E. salmonis, polar tube precursors fuse directly at their ends and the polar tubes appear to be formed by the assemblage of these fused precursors with a material previously synthesized in the vicinity of nuclei. In conclusion, both species appear to be less closely related than was supposed in earlier descriptions.


Zebrafish | 2006

Molecular Analysis of the Sex-Determining Region of the Platyfish Xiphophorus maculatus

Christina Schultheis; Qingchun Zhou; Alexander Froschauer; Indrajit Nanda; Yvonne Selz; Cornelia Schmidt; Sabine Matschl; Marina Wenning; Anne Marie Veith; Mariam Naciri; Reinhold Hanel; Ingo Braasch; Agnès Dettai; Astrid Böhne; Catherine Ozouf-Costaz; Stefan Chilmonczyk; Béatrice Segurens; Arnaud Couloux; Sylvie Bernard-Samain; Manfred Schartl; Jean Nicolas Volff

Due to the presence of genetically well-defined sex chromosomes, with a relatively restricted sex-determination region containing markers identified at the molecular level, the platyfish Xiphophorus maculatus is one of the best models for the positional cloning of a master sex-determining gene in fish. Both male and female heterogametes and three different types of sex chromosomes have been described in the platyfish, with several loci involved in pigmentation, melanoma formation, and sexual maturity closely linked to the master sex-determining locus. Using the melanoma-inducing oncogene Xmrk, its protooncogenic counterpart egfrb, as well as other X- and Y-linked molecular markers, bacterial artificial chromosome (BAC) contigs have been assembled for the sex-determining region of X. maculatus, which was mapped by fluorescent in situ hybridization to the subtelomeric region of the sex chromosomes. Initial sequence analysis of these contigs revealed several gene candidates and uncovered syntenies with different mammalian and chicken autosomes, supporting an independent origin of sex chromosomes in platyfish and tetrapods. Strikingly, the sex determination region of the platyfish is very instable and frequently undergoes duplications, deletions, and transpositions. This instability might be linked to the high genetic variability affecting sex determination and other sex-linked traits in Xiphophorus.

Collaboration


Dive into the Stefan Chilmonczyk's collaboration.

Top Co-Authors

Avatar

P. de Kinkelin

Institut national de la recherche agronomique

View shared research outputs
Top Co-Authors

Avatar

Catherine Ozouf-Costaz

Centre national de la recherche scientifique

View shared research outputs
Top Co-Authors

Avatar

Bernard Charley

Institut national de la recherche agronomique

View shared research outputs
Top Co-Authors

Avatar

Béatrice Riteau

Institut national de la recherche agronomique

View shared research outputs
Top Co-Authors

Avatar

Michel Bonneau

Institut national de la recherche agronomique

View shared research outputs
Top Co-Authors

Avatar

Vanessa Contreras

Institut national de la recherche agronomique

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Avi Eldar

Hebrew University of Jerusalem

View shared research outputs
Top Co-Authors

Avatar

Marina Eyngor

Hebrew University of Jerusalem

View shared research outputs
Top Co-Authors

Avatar

Arnaud Couloux

Centre national de la recherche scientifique

View shared research outputs
Researchain Logo
Decentralizing Knowledge