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Anaplasma phagocytophilum are obligatory intracellular bacteria that preferentially replicate inside leukocytes by utilizing biological compounds and processes of these primary host defensive cells. In this study, bioinformatics analysis was conducted to further characterize A. phagocytophilum– host interactions using the neutrophil-like model of human Caucasian promyelocytic leukemia HL60 cells. We detected a hierarchy of molecules involved in A. phagocytophilum-HL60 interactions with overrepresentation in infected human cells of proteins involved in the reactive oxygen species (ROS) pathway and cell surface monocyte markers. As A. phagocytophilum phagocytosis by neutrophils is inhibited, the results suggested a possible explanation for our bioinformatics data: radical oxygen compounds could induce the killing of bacteria activating NETosis, a unique form of defense mechanism resulting in cell death that is characterized by the release of decondensed chromatin and granular contents to the extracellular space, forming neutrophil extracellular traps (NETs) to eliminate invading microorganisms. Thus, we confirmed the existence of a low NETosis induced in A. phagocytophilum- infected cells by immunofluorescence (IF) experiments. These results provide new insights into the complex mechanisms that govern immune response during A. phagocytophilum host interactions.

Hyperbaric oxygen therapy (HBOT) has been used as treatment for different clinical conditions, including fibromyalgia (FM). HBOT modulates brain activity, ameliorates chronic pain and modifies the ratio of immune cells. Clinical studies have provided evidence that FM is associated with immune system dysregulation. In the present study we aimed to evaluate the effect of HBOT on immune system and on the quality of life-style of FM patients.Patients with primary FM and controls were treated with HBOT. Physical, emotional and social assessment, quality of sleep, tender points, intensity score, WPI and symptom severity were evaluated before and after HBOT. Furthermore, a characterisation of CD4 T lymphocytes and their cytokine production was performed by flow cytometry. The expression of TNF-α, IFN-γ, IL-17, IL-9 and IL-22 was also assessed by RT-PCR. Finally, the serum levels of serotonin were evaluated by ELISA.Our results confirm the participation of immune system in the pathogenesis of FM and highlight the impact of HBOT treatment, with particular regard to the changes on proinflammatory cytokines production by CD4 T cells subsets.FM patients show a Th1 signature and the activation of this subset is modulated by HBOT.

OBJECTIVES: Vitamin D status influences the risk to develop autoimmune diseases affecting the percentage and/or functions of regulatory T cells (Tregs). Since low levels of 25 (OH) D have been decreased in patients with systemic sclerosis (SSc), we aimed to study the effect of Vitamin D3 (cholecalciferol) supplementation on Tregs frequencies and functions. METHODS: Peripheral blood and sera samples were obtained from 45 SSc patients and controls (HC). A number of eighteen SSc patients had consumed Cholecalciferol (orally) at the dose of 25.000 UI/month for 6 months at the time of enrollment. 25(OH)D serum levels were measured and VDR polymorphisms, were genotyped by polymerase chain reaction (PCR). Tregs isolated from peripheral blood mononuclear cells were in vitro expanded and a suppression assay was performed. Flow cytometry analysis was then carried out. Finally, IL-10 production was assayed by ELISA. RESULTS: Low serum levels of 25(OH)D were detected in SSc patients. The percentage of Tregs in SSc patients was similar to controls, but, among SSc patients, it was higher in those patients taking cholecalciferol. Tregs capability to suppress T cell proliferation was impaired in SSc patients and not restored after in vitro pre-treatment with the active form of Vitamin D (1,25(OH)2D3); but at the same time the production of IL-10 was increased in treated samples obtained from patients. The lack of response of Tregs from SSc patients to 1,25(OH)2D3 treatment in vitro was not due to altered Vitamin D/VDR signalling. CONCLUSIONS: Altogether, our results indicate that the increased production of IL-10 by 1,25(OH)2D3 -treated Tregs could provide a "suppressive" cytokine milieu able to modulate immune response but it is not sufficient to restore the immune suppressive functions of Tregs.

OBJECTIVES: Invariant NKT (iNKT) cells play a role in regulating the function of autoreactive B cells before their entry into germinal centres. Absence and/or reduction of iNKT cells have been demonstrated in patients with systemic lupus erythematosus (SLE) together with an increase of autoreactive B cell activity. Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease in which lymphocyte infiltration and organisation in lymphoid structures of inflamed salivary glands occurs. The aim of the study was to investigate the percentage and function of iNKT in the salivary glands and peripheral blood of patients with pSS. METHODS: Minor salivary gland biopsies were obtained from patients with pSS and with non-specific chronic sialoadenitis (nSS). Flow cytometry analysis of CD1d/α-GalactosylCeramide (α-GalCer) tetramer positive cells, producing IFN-γ and IL-17, and quantitative gene expression analysis by TaqMan real-time PCR for Vα24 were performed on salivary glands biopsies and peripheral blood samples obtained from patients and controls. Flow cytometry and immunofluorescence analysis for autoreactive B lymphocytes and ELISA for anti-SSA antibodies (Ab) detection were also performed. RESULTS: An increase of iNKT was detected ex vivo in peripheral blood of pSS patients; after α-GalCer stimulation this subset produce IL-17 and IFN-iNKT were undetectable in the salivary glands of pSS patients and anti-SSA specific B cells were found in target tissue. Invariant NKT cells were able to inhibit autoantibody production by B cells obtained from salivary glands of pSS. CONCLUSIONS: Impaired iNKT migration to inflamed sites might induce the activation of autoreactive B cells specific for SSA-antigen in salivary glands of pSS patients.

Babesiosis due to Babesia bigemina is a relevant tick‑borne disease, affecting cattle worldwide. Many surface proteins of the pathogen including the Apical Membrane Antigen 1 (AMA‑1) ‑ have been analysed for vaccine and diagnostic purposes. This study focused on B. bigemina AMA‑1 and on its use for the assessment of diagnostic tests. After bioinformatic analyses, AMA‑1 codifying region was amplified and cloned into an expression vector used to induce protein synthesis in Escherichia coli cells. AMA‑1 was purified by affinity chromatography and used to set up the best condition for an ELISA protocol. Bovine field sera positive to B. bigemina were used to evaluate the presence of anti‑AMA‑1 antibodies. In order to verify the assay specificity, sera positive to Babesia bovis or to the piroplasm Theileria annulata were also included. Significant differences were obtained between sera negative to both B. bigemina and B. bovis and samples positive to B. bigemina, to B. bovis or to both pathogens. No significant reaction was observed with T. annulata positive sera. The results showed that AMA‑1 protein is suitable to be used as antigen in diagnostic assays for babesiosis diagnosis in cattle, as it does not show any cross reaction with anti-T. annulata antibodies.

OBJECTIVES: To investigate the in vitro and ex-vivo effect of IL-6 inhibition on the balance between Th1, Th2, Th17 and Treg cells. METHODS: Ten consecutive adult patients with active early rheumatoid arthritis (ERA) and ten healthy volunteers were included in the study. The percentages of Th1, Th2, Th17 and Treg cells were analysed by flow cytometry in the peripheral blood mononuclear cells obtained from controls and from RA patients at the time of first evaluation and just before the third TCZ infusion. The in vitro effect of TCZ on the different subsets of CD4+ T cells and the expression levels of Th1, Th2, Th17 and Treg-related cytokines was also assessed. RESULTS: Treatment with TCZ, both ex vivo and in vitro, resulted in a significant reduction of the percentage of Th1, Th17 and Treg cells with a concomitant significant increase of Th2 cell subsets. The reduction of the different subsets of T lymphocytes was associated with an intense staining with Annexin V, suggesting an apoptotic-related cell reduction. A significant decrease of Th1, Th17 and Treg cytokines and a concomitant increase of IL-4 was also observed after TCZ treatment in PBMC isolated from RA patients. CONCLUSIONS: TCZ could modify the immune imbalance in RA inducing apoptosis of Th1, Th17 and Treg cells and promoting the appearance of a Th2 response.

Background: Interleukin (IL)-22 is a potent mediator of cellular inflammatory responses that has been recently reported to play a role in the pathogenesis of primary Sjogren's Syndrome (p-SS) (1, 2) and of T and B lymphomas. IL-22 biological activity is initiated by binding to a cell-surface complex composed of two subunits, IL-22R1 and IL-10R2 receptor chains, and further regulated by interactions with a soluble binding protein, IL-22BP. Unlike the IL-10R2, which is constitutively expressed in many human tissues, IL-22R1 is not detectable in immune cells. Objectives: Aim of this study was to better characterize the role of IL-22 axis in the pathogenesis of p-SS and p-SSassociated lymphomas. Methods: Minor salivary gland biopsies were obtained from 30 patients with p-SS and 20 with non-specific chronic sialoadenitis (n-SS) and evaluated by RT-PCR for IL-22, IL-22R1 and IL-22BP expression. The protein expression of IL-22, IL- 22R1 and p-STAT3 was evaluated by immunohistochemistry and IL-22R1-expressing cells were caharcterized by confocal microscopy. Flow cytometry analysis of IL-22R1 expression was also conducted on peripheral blood mononuclear cells (PBMCs) from p-SS (n=30), n-SS (n=20), SLE (n=20) and rheumatoid arthritis (n=20) patients and normal controls (n=30). PBMCs isolated from 10 p-SS and 10 controls were also cultured with (or without) recombinant IL- 22 and the modulation of the transcripts for pro-inflammatory cytokines was assessed by RT-PCR. Paraffin embedded sections of non-Hodgkin lymphomas from 5 p-SS patients were finally evaluated for the expression of IL-22R1. Results: IL-22, STAT3 and IL-22BP but not IL-22R1 transcript levels were significantly up-regulated in the inflamed salivary glands of p-SS but not in n-SS. Immunohistochemistry confirmed the increased salivary expression of IL-22 and p-STAT3 also demonstrating a significant increased protein levels of IL-22R1 in p-SS. Confocal microscopy analysis showed that IL-22R1 was aberrantly and strongly expressed in monocytes/macrophages infiltrating the p-SS salivary glands and these cells also co-expressed p-STAT3, suggesting the occurrence of autocrine activation of p-STAT3. CD68+ cells obtained from the peripheral blood also aberrantly expressed IL-22R1 in p-SS patients. IL-22R1 expression on cells of hematopoietic origin was never observed in control disease patients, n-SS and healthy controls. The stimulation with recombinant IL-22 of PBMCs from p-SS but not controls significantly up-regulated the expression of IL-17 and IL-22. Non-Hodgkin lymphoma tissues from p-SS patients were also characterized by the aberrant expression of IL- 22R1 on macrophages and neoplastic B cells. Conclusions: The aberrant expression of IL-22RA1 on cells of hematopoietic origin seems to be a specific immunological signature of patients with p-SS and p-SS associated lymphomas and suggests a fundamental role of IL-22 signaling in the pathogenesis of p-SS and its neoplastic evolution. Targeting of IL-22 pathway may represent a successful therapeutic strategy in p-SS patients. References: 1. Ciccia F, et al. Ann RheumDis 2012. 2. Ciccia F, et al. Ann Rheum Dis 2012.

Objectives. To investigate the expression of IL-34 in labial salivary glands (LSGs) of patients with primary SS (p-SS) and its role in inducing a pro-inflammatory monocyte phenotype. Methods. LSG biopsies were obtained from 20 patients with p-SS and 10 patients with non-Sjögren's sicca syndrome (n-SS). The expression of IL-34, IL-1β, TNF-α, IL-17 and IL-23 was assessed by real-time PCR. IL-34 expression was also investigated in LSGs by immunohistochemistry. The frequencies of subpopulations of CD14+ monocytes were evaluated by flow cytometry among isolated mononuclear cells from peripheral blood and salivary glands from both patients and controls. The role of recombinant IL-34 on isolated peripheral blood mononuclear cells was also evaluated. Results. IL-34 m-RNA was overexpressed in the inflamed salivary glands of p-SS and associated with increased expression of TNF-α, IL-1β, IL-17 and IL-23p19. The increased expression of IL-34 was confirmed by immunohistochemistry in paraffin-embedded salivary glands from p-SS patients. IL-34 expression was accompanied by the expansion of pro-inflammatory CD14brightCD16+ monocytes in the salivary glands. In vitro stimulation of peripheral blood mononuclear cells with IL-34 induced the expansion of both CD14+CD16- cells and CD14brightCD16+ cells in p-SS and non-SS subjects. Conclusion. IL-34 seems to be involved in the pathogenesis of salivary gland inflammation in p-SS.

The article, “ -Galactosylceramide induces protection against lipopolysaccharide-induced shock” (doi:10.1189/jlb.0506298), was selected as a Pivotal Advance because the results suggest that -galactosylceramide ( GalCer), a glycolipid isolated from marine sponges, can protect against the complete morbidity and mortality characterisitic of endotoxin shock by inducing NKT cells to produce TH2 cytokines.

This paper describes the development of Ag-specific proliferation and the production of IFN-gamma and IL-2 during contact sensitivity (CS) to the hapten picryl chloride (PCl). Lymph node cells from mice immunized with PCl proliferate and produce IFN-gamma and IL-2 when re-exposed to the specific Ag in vitro. Time course experiments showed that the peak IFN-gamma production occurred at days 3 and 4 after immunization, with a sharp decline by day 6. In contrast, proliferation and IL-2 production peaked at day 3 but persisted up to day 10. Proliferation and IFN-gamma and IL-2 production displayed by immune lymph node cells were Ag-specific but required different cell populations. In fact, the production of IFN-gamma was due to a CD8+, gamma delta+ T cell, while proliferation and IL-2 production required the presence of a CD4+, alpha beta+ T cell. Furthermore, IFN-gamma production showed genetic (MHC) restriction, and finer analysis using congenic strains of mice indicated that the K molecule was the restricting element. This was confirmed by blocking the K molecule of the APC used to trigger IFN-gamma production with a specific mAb. In contrast, proliferation and IL-2 production were I-A-restricted, as demonstrated using congenic strains of mice and blocking the I-A molecule of the APCs. Further analysis using purified gamma delta+ cells revealed that these cells produced IFN-gamma in an Ag-specific and MHC (K)-restricted fashion. Injection of mice with a mAb to IL-2 blocked subsequent in vitro proliferation, as well as IL-2 and IFN-gamma production, while all three in vitro responses were unaffected by injection of a mAb to IFN-gamma given at the time of immunization. Furthermore, injection of mice with a mAb to IL-2 blocked the CS reaction when given at the time of immunization, while it had no effect when given at the time of challenge. Injection of mice with mAb to IFN-gamma at the time of challenge reduced but did not abolished CS, suggesting that IFN-gamma is important but not exclusively responsible for the CS reaction.

Vdelta2 T lymphocytes recognize nonpeptidic antigens without presentation by MHC molecules and mount both immediate effector functions and memory responses after microbial infection. However, how Vdelta2 T cells mediate different facets of a memory response remains unknown. Here, we show that the expression of CD45RA and CD27 antigens defines four subsets of human Vdelta2 T cells with distinctive compartmentalization routes. Naive CD45RA+CD27+ and memory CD45RA-CD27+ cells express lymph node homing receptors, abound in lymph nodes, and lack immediate effector functions. Conversely, memory CD45RA-CD27- and terminally differentiated CD45RA+CD27- cells, which express receptors for homing to inflamed tissues, are poorly represented in the lymph nodes while abounding at sites of inflammation, and display immediate effector functions. These observations and additional in vitro experiments indicate a lineage differentiation pattern for human Vdelta2 T cells that generates naive cells circulating in lymph nodes, effector/memory cells patrolling the blood, and terminally differentiated effector cells residing in inflamed tissues.

BACKGROUND: The recognition of phosphorylated nonpeptidic microbial metabolites by Vgamma9Vdelta2 T cells does not appear to require the presence of MHC molecules or antigen processing, permitting rapid responses against microbial pathogens. These may constitute an important area of natural anti-infectious immunity. To provide evidence of their involvement in immune reactivities against mycobacteria, we measured the responsiveness of peripheral blood Vgamma9Vdelta2 T cells in children with primary Mycobacterium tuberculosis (MTB) infections. MATERIALS AND METHODS: Peripheral blood mononuclear cells from 22 children with MTB infections and 16 positivity of tuberculin (PPD)-negative healthy children were exposed to nonpeptidic antigens in vitro and the reactivity of the Vgamma9Vdelta2 T cell subset with these antigens was determined using proliferation and cytokine assays. Also, responses of gammadelta T cells from rhesus monkeys stimulated with phosphoantigens in vivo were measured. RESULTS: The Vgamma9Vdelta2 T cell responses were highly increased in infected children in comparison with age-matched controls. This augmented Vgamma9Vdelta2 T cell reactivity subsided after successful antibiotic chemotherapy, suggesting that persistent exposure to mycobacterial antigens is required for the maintenance of gammadelta T cell activation in vivo. The in vivo reactivity of Vgamma9Vdelta2 T cells to phosphoantigens was also analyzed in a rhesus monkey model system. Intravenous injections of phosphoantigens induced an activated state of simian Vgamma9Vdelta2 T cells which decreased after 2 months, i.e., with a time course similar to that seen in MTB-infected children. CONCLUSIONS: The increased reactivity of Vgamma9Vdelta2 T cells to phosphoantigens appears to be dependent on constant antigenic exposure. Consequently, the assessment of Vgamma9Vdelta2 responses may be useful for monitoring the efficacy of antimycobacterial therapies.

We have previously reported that T lymphocytes proliferating in vitro to the hapten trinitrochlorobenzene (TNCB) exhibit a very restricted V beta gene usage and response to TNCB is limited to T-cell receptors (TCR) composed of V beta 8.2 in combination with V alpha 3.2, V alpha 8 and V alpha 10. This paper investigates the role played by T lymphocytes expressing the V beta 8.2 gene segment in the contact sensitivity (CS) reaction to TNCB in the intact mouse and in its passive transfer into naive recipient mice. Mice injected with monoclonal antibodies to V beta 8 are unable to develop CS upon immunization with TNCB and 4-day TNCB-immune lymph node cells from mice that had been depleted in vivo or in vitro of V beta 8+ T lymphocytes fail to transfer CS. However, when separated V beta 8+ and V beta 8- cells were used for passive transfer, it was found that V beta 8+ T lymphocytes failed to transfer CS when given alone to recipient mice and a V beta 8- population was absolutely required. Further analysis revealed that within the V beta 8- population, T lymphocytes expressing the gamma delta TCR were fundamental to allow transfer of the CS reaction. These gamma delta cells were found to be antigen non-specific, genetically unrestricted and to rearrange the V gamma 3 gene segment. This indicates that transfer of the CS reaction requires cross-talk between V beta 8+ and gamma delta+ T lymphocytes, thus confirming our previous results obtained using TNCB-specific T-cell lines. Time-course experiments showed that V beta 8+ lymphocytes taken 4-24 days after immunization with TNCB were able to proliferate and produce interleukin-2 (IL-2) in response to the specific antigen in vitro. Similar time-course experiments were then undertaken using the passive transfer of the CS reaction system. The results obtained confirm that TNCB-specific V beta 8+ T lymphocytes are present in the lymph nodes of immunized mice from day 4 to day 24, and reveal that gamma delta+ T lymphocytes are active for a very short period of time, i.e. days 4 and 5 after immunization. In fact, TNCB-specific V beta 8+ cells are able to transfer CS when taken 4-24 days after immunization, providing the accompanying V beta 8- or gamma delta+ T lymphocyte are obtained 4 days after immunization. In contrast, injection of V beta 8+ T lymphocytes together with V beta 8- or gamma delta+ T lymphocytes that had been taken 2 or 6 days after immunization, failed to transfer significant CS into recipient mice. Taken together, our results confirm that cross-talk between V beta 8+ and gamma delta+ T lymphocytes is necessary for full development of the CS reaction and may explain why the CS reaction in the intact mouse lasts up to 21 days after immunization while the ability of immune lymph node cells to transfer CS is limited to days 4 and 5 after immunization.

This paper investigates the V beta usage of lymph node cells from mice immunized with TNP and of cell lines made from them. In cell lines stimulated weekly with TNP in vitro for 1 month, about 87% of the cells were V beta 8+ and further analysis showed that these cells were actually V beta 8.2+. This was also true for the cells that proliferated in lymph nodes in response to TNP 4 days after primary immunization, i.e. proliferation occurred mainly in the V beta 8+, and in particular in the V beta 8.2+, population while much less proliferation occurred when the V beta 8- or V beta 8.2- T-cell populations are used. This was not due to non-specific damage during separation, as the response to concanavalin A and alloantigen was intact. In a separate series of experiments, mice were acutely depleted of V beta 8+ T cells by treatment with F23.1 or a control monoclonal antibody (mAb) in vivo given before immunization. Treatment with the relevant mAb virtually abolished the response to TNP. In contrast, SJL mice, which lack the gene segment coding for the V beta 8 family and several other V beta chains, made a normal proliferative and delayed-type hypersensitivity (DTH) response to TNP. This poses the problem, which may be important in the study of the T-cell repertoire, of why acute removal of V beta 8+ T cells, which are dominantly used in the response to TNP, does not allow T cells using other chains to substitute in the response, while the absence of this population over a long period of time, because of a deletion in the genome, allows the use of T cells bearing other V beta chains.