Joint inflammations and exacerbations in mice by cloned helper T cells

Briefly, the aim of the study described in this thesis was to investigate whether the joint inflammations that occur in AlA can also be induced by cloned helper T cells and the antigen they recognize, and whether these joint inflammations can also show flare-up phenomena after repeated administration of the antigen. In Chapter 2 it is shown that cloned T cells with the helper phenotype can induce delayed type hypersensitivity (DTH) reactions and that these reactions can give rise to flare-up reactions after local, iv or oral administration of the antigen. We hypothesized that these DTH reactions underly the development of joint inflammations in the AlA model, and presumably in human rheumatoid diseases. In Chapter 3 we present the model of induction of joint inflammation by similar cloned T cells. Dose response curves of the antigen and the cloned T cells injected into the joints are shown, as are the kinetics of the joint inflammations induced. Furthermore we show that it is possible to evoke flare-up reactions of these joint inflammations, but also of joint inflammations induced by systemically administered T cells and local injection of the antigen. The induction of joint inflammation by the cloned T cells was found to be dependent on H-2 restricted interactions with recipient cells or tissues. In Chapter 4 we show that both the joint inflammation and the flareup reactions can be evoked in T cell deficient nude mice as well. Furthermore, this paper pays attention to the role of antigen in the retention of the cloned T cells in the joint. In our model, the induction of an inflammatory reaction is dependent on H-2 restricted interactions between T cells and recipient cells and tissues, presumably antigen presenting cells. In Chapter 5 the characterization of a macrophage cell line, AP284, is described that is able to present antigen efficiently in vivo to the cloned helper T cells used in our studies. Injection of AP284 and syngeneic cloned helper T cells into the hind foot of allogeneic mice induces a full blown DTH reaction. This model, in which both the antigen presenting cells and the T cells are monoclonal, is attractive to investigate the cellular interactions in the induction of T cell dependent inflammations. Therefore we applied this approach in our studies on AlA to investigate whether antigen activated helper T cells and macrophages are sufficient for the induction of joint inflammation in allogeneic recipients. The data presented in Chapter 6 show that this was indeed the case. Finally in Chapter 7 we studied in detail the histological and immunohistochemical characteristics of the inflammations and flare-up reactions in our model. The data emerging from our studies are discussed in the perspective of literature data in Chapter

Arthritis by autoreactive T cell lines obtained from rats after injection of intestinal bacterial cell wall fragments

__Abstract__ T cell lines (B13, B19) were isolated from the lymph nodes of Lewis rats 12 days after an arthritogenic injection of cell wall fragments of Eubacterium aerofaciens (ECW), a major resident of the human intestinal flora. These cell wall fragments consist of peptidoglycan polysaccharide complexes (PPC). The cell lines that bear the helper phenotype were arthritogenic in knee or ankle joints upon intravenous injection into irradiated Lewis recipients. B13 was, however, not arthritogenic in irradiated F344 recipients that are largely RT1 identical. The arthritis induced in the knee joints of the irradiated Lewis rats was clearly shown by a 99mtechnetium-pertechnetate scanning technique and was confirmed histologically. In vitro the cell lines showed a proliferative response after stimulation with syngeneic spleen cells alone. The proliferation was significantly higher when bacterial PPC, isolated in soluble form from normal feces or ileostomy fluid were added. Recognition by B13 appeared to be MHC class II restricted. These results show that autoreactive T cell lines can be isolated from rats after injection of bacterial cell wall antigens and that these cell lines can be arthritogenic. This suggests a role for autoreactive T cells in the induction of bacterial cell wall arthritis and might give a clue for the arthritogenic properties of the normal human intestinal flora

Histological and immunohistochemical characterization of joint inflammation and flare-up reactions induced by cloned MT4+, Lyt-2-T cells

Abstract This report describes the histological and immunohistochemical characterization of joint inflammations and flare-up reactions in mice induced by cloned MT4+, Lyt-2− T cells. The T-cell clone used was specific for the antigen methylated bonne serum albumin (mBSA) and was inoculated locally into a joint together with the antigen. The histological examination was performed in methylmethacrylate sections, and the various cell types were quantified m distinct regions of the knee joint. The infiltrates consisted predominantly or granulocytes admixed with small numbers of histiocytes. Few lymphocytes were present, while plasma cells were not found. Fibrosis was prominent in the later stages of the inflammation. Immunohistochemical analysis of total unfixed, non-decalcified sections using monoclonal antibodies revealed the presence of T cells which were predominantly of the helper phenotype. sporadic B cells, and a considerable number of la-positive cells. Macrophages were scattered throughout the infiltrate. The synovial lining was shown to express Ia antigens and to contain cells that stained with macrophage markers Cell clusters were found including helper T (Th) cells, some B cells, and Ia-positive cells. These results are in line with immunohistological examinations in other arthritis models and resemble the early events in human rheumatoid arthritis. The data indicate that activated helper T cells are required and sufficient to give rise to the inflammatory infiltrates that are characteristic of the inflammations and exacerbations in human rheumatoid arthritis

Plasmacytoid dendritic cells of melanoma patients present exogenous proteins to CD4+ T cells after FcγRII-mediated uptake

Plasmacytoid dendritic cells (pDCs) contribute to innate antiviral immune responses by producing type I interferons. Although human pDCs can induce T cell responses upon viral infection, it remains unclear if pDCs can present exogenous antigens. Here, we show that human pDCs exploit FcγRII (CD32) to internalize antigen–antibody complexes, resulting in the presentation of exogenous antigen to T cells. pDCs isolated from melanoma patients vaccinated with autologous monocyte-derived peptide- and keyhold limpet hemocyanin (KLH)–loaded dendritic cells, but not from nonvaccinated patients or patients that lack a humoral response against KLH, were able to stimulate KLH-specific T cell proliferation. Interestingly, we observed that internalization of KLH by pDCs depended on the presence of serum from vaccinated patients that developed an anti-KLH antibody response. Anti-CD32 antibodies inhibited antigen uptake and presentation, demonstrating that circulating anti-KLH antibodies binding to CD32 mediate KLH internalization. We conclude that CD32 is an antigen uptake receptor on pDCs and that antigen presentation by pDCs is of particular relevance when circulating antibodies are present. Antigen presentation by pDCs may thus modulate the strength and quality of the secondary phase of an immune response

The presence of Peptidoglycan-Polysaccharide complexes in the bowel wall and the cellular responses to these complexes in Crohn's disease

Interestingly, using a monoclonal antibody, peptidoglycan-polysaccharide complexes (PPC) were detected intracellularly in the mucosa and submucosa of the bowel wall of Crohn's disease (CD) patients. PPC are the main constituents of the gram-positive bacterial cell wall. These PPC were however detected in the normal bowel wall also. Therefore, in this study the hypothesis that an enhanced immune responsiveness to bacterial antigens plays a pivotal role in the induction or the chronicity of CD was tested. As antigens, the peptidoglycan structures of intestinal bacteria (Eubacterium aerofaciens or fecal PPC) or of Streptococcus pyogenes, the 65-kDa heat shock protein and muramyl dipeptide (MDP), the smallest bioactive subunit of peptidoglycan, were used. The proliferative responses of peripheral blood (PB) mononuclear cells (MNC) of healthy subjects and patients in a remissive stage of CD or an active CD stage were examined. Of this last patient group the MNC responses of the mesenterial lymph nodes that drain the inflamed gut area were measured also. The responses of PBMNC of the healthy subjects and the patients in a remissive CD stage were not different. Compared to the responses in remissive CD, the PB-MNC responses in active CD to the eubacterial cell wall and streptococcal cell wall antigen were significantly higher. At the inflammation site in active CD, the lymph nodes, the responses to most of the bacterial antigens were significantly higher than in the PB. In summary, the results show the presence of bacterial peptidoglycan in the bowel wall and the immune responsiveness, especially at the inflammation site, to these antigens in active CD and therefore present suggestive evidence for the role of peptidoglycan in the etiology and/or pathogenesis of CD

Dendritic cell vaccination in combination with anti-CD25 monoclonal antibody treatment: a phase I/II study in metastatic melanoma patients.

Contains fulltext : 88281.pdf (publisher's version ) (Closed access)PURPOSE: The success of cancer immunotherapy depends on the balance between effector T cells and suppressive immune regulatory mechanisms within the tumor microenvironment. In this study we investigated whether transient monoclonal antibody-mediated depletion of CD25(high) regulatory T cells (Treg) is capable of enhancing the immunostimulatory efficacy of dendritic cell vaccines. EXPERIMENTAL DESIGN: Thirty HLA-A2.1(+) metastatic melanoma patients were vaccinated with mature dendritic cells pulsed with tumor peptide and keyhole limpet hemocyanin (KLH). Half of the patients were pretreated with daclizumab, a humanized antibody against the interleukin-2 (IL-2) receptor alpha-chain (CD25), either four or eight days before dendritic cell vaccinations. Clinical and immunologic parameters were determined. Results : Daclizumab efficiently depleted all CD25(high) immune cells, including CD4(+)FoxP3(+)CD25(high) cells, from the peripheral blood within four days of administration. Thirty days after administration, daclizumab was cleared from the circulation and all CD25(+) cells reappeared. The presence of daclizumab during dendritic cell vaccinations prevented the induction of specific antibodies in vivo but not the presence of antigen-specific T cells. Daclizumab, however, did prevent these CD25(+) T cells from acquiring effector functions. Consequently, significantly less patients pretreated with daclizumab developed functional, vaccine-specific effector T cells and antibodies compared with controls. Daclizumab pretreatment had no significant effect on progression-free survival compared with the control group. CONCLUSIONS: Although daclizumab depleted the CD4(+)FoxP3(+)CD25(high) Tregs from the peripheral circulation, it did not enhance the efficacy of the dendritic cell vaccine. Residual daclizumab functionally suppressed de novo induced CD25(+) effector cells during dendritic cell vaccinations. Our results indicate that for immunotherapeutic benefit of transient Treg depletion, timing and dosing as well as Treg specificity are extremely important

The Forward Physics Facility at the High-Luminosity LHC

High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe standard model (SM) processes and search for physics beyond the standard model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential

The Forward Physics Facility at the High-Luminosity LHC

International audienceHigh energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe Standard Model (SM) processes and search for physics beyond the Standard Model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential