Endothelial TNF receptor 2 induces IRF1 transcription factor-dependent interferon-ß autocrine signaling to promote monocyte recruitment.

Endothelial-dependent mechanisms of mononuclear cell influx are not well understood. We showed that acute stimulation of murine microvascular endothelial cells expressing the tumor necrosis factor receptors TNFR1 and TNFR2 with the soluble cytokine TNF led to CXCR3 chemokine generation. The TNF receptors signaled through interferon regulatory factor-1 (IRF1) to induce interferon-ß (IFN-ß) and subsequent autocrine signaling via the type I IFN receptor and the transcription factor STAT1. Both TNFR2 and TNFR1 were required for IRF1-IFNß signaling and, in human endothelial cells TNFR2 expression alone induced IFN-ß signaling and monocyte recruitment. In vivo, TNFR1 was required for acute renal neutrophil and monocyte influx after systemic TNF treatment, whereas the TNFR2-IRF1-IFN-ß autocrine loop was essential only for macrophage accumulation. In a chronic model of proliferative nephritis, IRF1 and renal-expressed TNFR2 were essential for sustained macrophage accumulation. Thus, our data identify a pathway in endothelial cells that selectively recruits monocytes during a TNF-induced inflammatory response.

Lung airway-surveilling CXCR3(hi) memory CD8(+) T cells are critical for protection against influenza A virus.

Inducing memory CD8(+) T cells specific for conserved antigens from influenza A virus (IAV) is a potential strategy for broadly protective vaccines. Here we show that memory CD8(+) T cells in the airways played an important role in early control of IAV. Expression of the chemokine receptor CXCR3 was critical for memory CD8(+) T cells to populate the airways during the steady state and vaccination approaches were designed to favor the establishment of memory CD8(+) T cells in the airways. Specifically, we found that interleukin-12 (IL-12) signaling shortly after immunization limited CXCR3 expression on memory CD8(+) T cells. Neutralization of IL-12 or adjuvants that did not induce high amounts of IL-12 enhanced CXCR3 expression, sustained airway localization of memory CD8(+) T cells, and resulted in superior protection against IAV.

CD8+ T cells in the central nervous system of mice with herpes simplex infection are highly activated and express high levels of CCR5 and CXCR3.

Herpes simplex virus type 2 (HSV-2) is a neurotropic virus that can cause meningitis, an inflammation of the meninges in the central nervous system. T cells are key players in viral clearance, and these cells migrate from peripheral blood into the central nervous system upon infection. Several factors contribute to T cell migration, including the expression of chemokines in the inflamed tissue that attract T cells through their expression of chemokine receptors. Here we investigated CD8+ T cell profile in the spinal cord in a mouse model of herpes simplex virus type 2 neuroinflammation. Mice were infected with HSV-2 and sacrificed when showing signs of neuroinflammation. Cells and/or tissue from spinal cord, spleen, and blood were analyzed for expression of activation markers, chemokine receptors, and chemokines. High numbers of CD8+ T cells were present in the spinal cord following genital HSV-2-infection. CD8+ T cells were highly activated and HSV-2 glycoprotein B -specific effector cells, some of which showed signs of recent degranulation. They also expressed high levels of many chemokine receptors, in particular CCR2, CCR4, CCR5, and CXCR3. Investigating corresponding receptor ligands in spinal cord tissue revealed markedly increased expression of the cognate ligands CCL2, CCL5, CCL8, CCL12, and CXCL10. This study shows that during herpesvirus neuroinflammation anti-viral CD8+ T cells accumulate in the CNS. CD8+ T cells in the CNS also express chemotactic receptors cognate to the chemotactic gradients in the spinal cord. This indicates that anti-viral CD8+ T cells may migrate to infected areas in the spinal cord during herpesvirus neuroinflammation in response to chemotactic gradients.

Induction of brain-infiltrating T-bet-expressing B cells in multiple sclerosis.

OBJECTIVE: Results from anti-CD20 therapies demonstrate that B- and T-cell interaction is a major driver of multiple sclerosis (MS). The local presence of B-cell follicle-like structures and oligoclonal bands in MS patients indicates that certain B cells infiltrate the central nervous system (CNS) to mediate pathology. Which peripheral triggers underlie the development of CNS-infiltrating B cells is not fully understood. METHODS: Ex vivo flow cytometry was used to assess chemokine receptor profiles of B cells in blood, cerebrospinal fluid, meningeal, and brain tissues of MS patients (n = 10). Similar analyses were performed for distinct memory subsets in the blood of untreated and natalizumab-treated MS patients (n = 38). To assess T-bet(CXCR3)+ B-cell differentiation, we cultured B cells from MS patients (n = 21) and healthy individuals (n = 34) under T helper 1- and TLR9-inducing conditions. Their CNS transmigration capacity was confirmed using brain endothelial monolayers. RESULTS: CXC chemokine receptor 3 (CXCR3)-expressing B cells were enriched in different CNS compartments of MS patients. Treatment with the clinically effective drug natalizumab prevented the recruitment of CXCR3high IgG1+ subsets, corresponding to their increased ability to cross CNS barriers in vitro. Blocking of interferon-γ (IFNγ) reduced the transmigration potential and antigen-presenting function of these cells. IFNγ-induced B cells from MS patients showed increased T-bet expression and plasmablast development. Additional TLR9 triggering further upregulated T-bet and CXCR3, and was essential for IgG1 switching. INTERPRETATION: This study demonstrates that T-bethigh IgG1+ B cells are triggered by IFNγ and TLR9 signals, likely contributing to enhanced CXCR3-mediated recruitment and local reactivity in the CNS of MS patients. ANN NEUROL 2019;86:264-278.

CD21-/low B cells associate with joint damage in rheumatoid arthritis patients.

Depletion of B cells is beneficial in rheumatoid arthritis (RA) patients with autoantibodies to citrullinated proteins (ACPA) and/or the Fc portion of immunoglobulins (rheumatoid factor [RF]), suggesting a role for B cells in disease pathogenesis. To date, however, the identity of specifically pathogenic B cell subsets has not been discovered. One candidate population is identified by the low expression or absence of complement receptor 2 (CD21-/low B cells). In this study, we sought to determine whether there was any correlation between CD21-/low B cells and clinical outcome in patients with established RA, either ACPA+ /RF+ (n = 27) or ACPA- /RF- (n = 10). Healthy donors (n = 17) were included as controls. The proportion of the CD21-/low CD27- IgD- memory B cell subset in peripheral blood (PB) was significantly increased in ACPA+ /RF+ RA patients compared with healthy donors, and the frequency of this subset correlated with joint destruction (r = 0.57, P < 0.04). The levels of the chemokines CXCL-9 and CXCL-10 were higher in synovial fluid than in plasma, and PB CD21-/low cells expressed the receptor, CXCR3. In synovial fluid, most of the B cells were CD21-/low , approximately 40% of that population was CD27- IgD- , and a third of those expressed the pro-osteoclastogenic factor receptor activator of the nuclear factor κB ligand (RANKL). This subset also secreted RANKL, in addition to other factors such as IL-6, even in the absence of stimulation. We interpret these data as reason to propose the hypothesis that the CD27- IgD- subset of CD21-/low B cells may mediate joint destruction in patients with ACPA+ /RF+ RA.

Selective Expression of CCR10 and CXCR3 by Circulating Human Herpes Simplex Virus-Specific CD8 T Cells.

Herpes simplex virus (HSV) infection is restricted to epithelial cells and neurons and is controlled by CD8 T cells. These cells both traffic to epithelial sites of recurrent lytic infection and to ganglia and persist at the dermal-epidermal junction for up to 12 weeks after lesion resolution. We previously showed that cutaneous lymphocyte-associated antigen (CLA), a functional E-selectin ligand (ESL), is selectively expressed on circulating HSV-2-specific CD8 T cells. CLA/ESL mediates adhesion of T cells to inflamed vascular endothelium. Later stages in T-cell homing involve chemokines (Ch) and lymphocyte chemokine receptors (ChR) for vascular wall arrest and diapedesis. Several candidate ChR have been implicated in skin homing. We measured cell surface ChR on HSV-specific human peripheral blood CD8 T cells and extended our studies to HSV-1. We observed preferential cell surface expression of CCR10 and CXCR3 by HSV-specific CD8 T cells compared to CD8 T cells specific for control viruses, Epstein-Barr virus (EBV) and cytomegalovirus (CMV), and compared to bulk memory CD8 T cells. CXCR3 ligand mRNA levels were selectively increased in skin biopsy specimens from persons with recurrent HSV-2, while the mRNA levels of the CCR10 ligand CCL27 were equivalent in lesion and control skin. Our data are consistent with a model in which CCL27 drives baseline recruitment of HSV-specific CD8 T cells expressing CCR10, while interferon-responsive CXCR3 ligands recruit additional cells in response to virus-driven inflammation.IMPORTANCE HSV-2 causes very localized recurrent infections in the skin and genital mucosa. Virus-specific CD8 T cells home to the site of recurrent infection and participate in viral clearance. The exit of T cells from the blood involves the use of chemokine receptors on the T-cell surface and chemokines that are present in infected tissue. In this study, circulating HSV-2-specific CD8 T cells were identified using specific fluorescent tetramer reagents, and their expression of several candidate skin-homing-associated chemokine receptors was measured using flow cytometry. We found that two chemokine receptors, CXCR3 and CCR10, are upregulated on HSV-specific CD8 T cells in blood. The chemokines corresponding to these receptors are also expressed in infected tissues. Vaccine strategies to prime CD8 T cells to home to HSV lesions should elicit these chemokine receptors if possible to increase the homing of vaccine-primed cells to sites of infection.

CXCR3 Blockade Inhibits T Cell Migration into the Skin and Prevents Development of Alopecia Areata.

Alopecia areata (AA) is an autoimmune disease of the hair follicle that results in hair loss of varying severity. Recently, we showed that IFN-γ-producing NKG2D(+)CD8(+) T cells actively infiltrate the hair follicle and are responsible for its destruction in C3H/HeJ AA mice. Our transcriptional profiling of human and mouse alopecic skin showed that the IFN pathway is the dominant signaling pathway involved in AA. We showed that IFN-inducible chemokines (CXCL9/10/11) are markedly upregulated in the skin of AA lesions, and further, that the IFN-inducible chemokine receptor, CXCR3, is upregulated on alopecic effector T cells. To demonstrate whether CXCL9/10/11 chemokines were required for development of AA, we treated mice with blocking Abs to CXCR3, which prevented the development of AA in the graft model, inhibiting the accumulation of NKG2D(+)CD8(+) T cells in the skin and cutaneous lymph nodes. These data demonstrate proof of concept that interfering with the Tc1 response in AA via blockade of IFN-inducible chemokines can prevent the onset of AA. CXCR3 blockade could be approached clinically in human AA with either biologic or small-molecule inhibition, the latter being particularly intriguing as a topical therapeutic.

Codelivery of Envelope Protein in Alum with MVA Vaccine Induces CXCR3-Biased CXCR5+ and CXCR5- CD4 T Cell Responses in Rhesus Macaques.

The goal of an HIV vaccine is to generate robust and durable protective Ab. Vital to this goal is the induction of CD4(+) T follicular helper (TFH) cells. However, very little is known about the TFH response to HIV vaccination and its relative contribution to magnitude and quality of vaccine-elicited Ab titers. In this study, we investigated these questions in the context of a DNA/modified vaccinia virus Ankara SIV vaccine with and without gp140 boost in aluminum hydroxide in rhesus macaques. In addition, we determined the frequency of vaccine-induced CD4(+) T cells coexpressing chemokine receptor, CXCR5 (facilitates migration to B cell follicles) in blood and whether these responses were representative of lymph node TFH responses. We show that booster modified vaccinia virus Ankara immunization induced a distinct and transient accumulation of proliferating CXCR5(+) and CXCR5(-) CD4 T cells in blood at day 7 postimmunization, and the frequency of the former but not the latter correlated with TFH and B cell responses in germinal centers of the lymph node. Interestingly, gp140 boost induced a skewing toward CXCR3 expression on germinal center TFH cells, which was strongly associated with longevity, avidity, and neutralization potential of vaccine-elicited Ab response. However, CXCR3(+) cells preferentially expressed the HIV coreceptor CCR5, and vaccine-induced CXCR3(+)CXCR5(+) cells showed a moderate positive association with peak viremia following SIV251 infection. Taken together, our findings demonstrate that vaccine regimens that elicit CXCR3-biased TFH cell responses favor Ab persistence and avidity but may predispose to higher acute viremia in the event of breakthrough infections.

CXCL9 Regulates TGF-ß1-Induced Epithelial to Mesenchymal Transition in Human Alveolar Epithelial Cells.

Epithelial to mesenchymal cell transition (EMT), whereby fully differentiated epithelial cells transition to a mesenchymal phenotype, has been implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). CXCR3 and its ligands are recognized to play a protective role in pulmonary fibrosis. In this study, we investigated the presence and extent of EMT and CXCR3 expression in human IPF surgical lung biopsies and assessed whether CXCR3 and its ligand CXCL9 modulate EMT in alveolar epithelial cells. Coexpression of the epithelial marker thyroid transcription factor-1 and the mesenchymal marker α-smooth muscle actin and CXCR3 expression was examined by immunohistochemical staining of IPF surgical lung biopsies. Epithelial and mesenchymal marker expression was examined by quantitative real-time PCR, Western blotting, and immunofluorescence in human alveolar epithelial (A549) cells treated with TGF-ß1 and CXCL9, with Smad2, Smad3, and Smad7 expression and cellular localization examined by Western blotting. We found that significantly more cells were undergoing EMT in fibrotic versus normal areas of lung in IPF surgical lung biopsy samples. CXCR3 was expressed by type II pneumocytes and fibroblasts in fibrotic areas in close proximity to cells undergoing EMT. In vitro, CXCL9 abrogated TGF-ß1-induced EMT. A decrease in TGF-ß1-induced phosphorylation of Smad2 and Smad3 occurred with CXCL9 treatment. This was associated with increased shuttling of Smad7 from the nucleus to the cytoplasm where it inhibits Smad phosphorylation. This suggests a role for EMT in the pathogenesis of IPF and provides a novel mechanism for the inhibitory effects of CXCL9 on TGF-ß1-induced EMT.

T-bet is critical for the development of acute graft-versus-host disease through controlling T cell differentiation and function.

T-bet is a master regulator for IFN-γ production and Th1 differentiation. We evaluated the roles of T-bet and IFN-γ in T cell responses in acute graft-versus-host disease (GVHD) and found that T-bet(-/-) T cells induced significantly less GVHD compared with wild-type or IFN-γ(-/-) counterparts in both MHC-mismatched and MHC-matched but minor histocompatibility Ag-mismatched models driven by CD4 T cells. T-bet(-/-), but not IFN-γ(-/-), CD4 T cells had a markedly reduced ability to cause tissue damage in liver and gut. This distinct outcome is reflected by the differential gene expression on donor CD4 T cells deficient for T-bet or IFN-γ. At mRNA and protein levels, we defined several T-bet-dependent molecules that may account for the impaired ability of T-bet(-/-) T cells to migrate into target organs and to produce Th1-related cytokines. Moreover, these molecules were independent of either endogenous IFN-γ, such as CXCR3 and programmed death-1, or systematic IFN-γ, such as NKG2D, I-A(b), and granzyme B. Although both T-bet(-/-) and IFN-γ(-/-) CD4 T cells are prone to differentiate into Th17 cells, polarized Th17 cells deficient for T-bet but not for IFN-γ had a significantly reduced ability to cause GVHD. Finally, T-bet(-/-) T cells had a compromised graft-versus-leukemia effect, which could be essentially reversed by neutralization of IL-17 in the recipients. We conclude that T-bet is required for Th1 differentiation and migration, as well as for optimal function of Th17 cells. Thus, targeting T-bet or regulating its downstream effectors independent of IFN-γ may be a promising strategy to control GVHD in the clinic.

Immunohistochemical distinction of metastases of renal cell carcinoma with molecular analysis of overexpression of the chemokines CXCR2 and CXCR3 as independent positive prognostic factors for the tumorigenesis.

Renal cell carcinoma (RCC) represents, on average, over 90% of all malignancies of the kidney that occur in adults in both sexes. Chemokine receptors expression has been found in many kinds of cancer and at tumor metastasis site. We determined CXCR2 and CXCR3 expression in RCC by immunohistochemistry method and analyzed the prognostic value of these markers. Our finding demonstrated that CXCR3 were highly overexpressed in renal cancer tissues compared with those adjacent normal kidney tissues (P < 0.001). The results showed that high expression of CXCR3 was markedly correlated with metastasis (P = 0.021) and tumor stage (P = 0.031). CXCR2 were overexpressed in renal cancer tissues compared with those adjacent normal kidney tissues (P < 0.001). Our result showed that CXCR2 expression was correlated with high grade (P = 0.024), advanced stage (P = 0.029) and metastasis (P = 0.018). The log-rank test revealed that high CXCR2 and CXCR3 expressions are related to poorer overall survival (P < 0.001; P < 0.001). In conclusion, this study indicates the correlation of CXCR3 and CXCR3 with progression of RCC. In addition, high CXCR3 andCXCR2 expressions were correlated with shorter overall survival. © 2016 IUBMB Life, 68(8):629-633, 2016.

Irradiation of breast cancer cells enhances CXCL16 ligand expression and induces the migration of natural killer cells expressing the CXCR6 receptor.

BACKGROUND AIMS: Few studies have examined the migration pattern of natural killer (NK) cells, especially after radiation treatment for cancer. We investigated whether irradiation can modulate the expression of chemokines in cancer cells and the migration of NK cells to irradiated tumor cells. METHODS: The expression of chemokine receptors (CXCR3, CXCR4 and CXCR6) on interleukin-2 (IL-2)/IL-15-activated NK cells was assessed using flow cytometry. Related chemokine ligands (CXCL11, CXCL12 and CXCL16) in human breast cancer cell lines (MCF7, SKBR3 and MDA-MB231) irradiated at various doses were assessed using reverse transcription-polymerase chain reaction (RT-PCR), fluorescence-activated cell sorting (FACS) and enzyme-linked immunosorbent assay (ELISA). The cell-free culture supernatant was collected 96 h after irradiation of breast cancer cell lines for migration and blocking assays. RESULTS: The activated NK cells expressed CXCR6. Expression of the CXCR6 ligand CXCL16 increased in a time- and dose-dependent manner in all analyzed cancer cell lines. CXCL16 expression was statistically significantly enhanced in all breast cancer cell lines on day 3 after 20 Gy irradiation. Activated NK cells migration correlated with CXCL16 concentration (R2 = 0.91; P <0.0001). Significantly enhanced migration of NK cells to irradiated cancer cells was observed for a dose of 20 Gy in MCF7 (P = 0.043) and SKBR3 (P = 0.043) cells, but not in MDA-MB231 (P = 0.225) cells. A blocking assay using a CXCR6 antibody showed a significant decrease in the migration of activated NK cells in all cancer cell lines. CONCLUSIONS: Our data indicate that irradiation induces CXCL16 chemokine expression in cancer cells and enhances the migration of activated NK cells expressing CXCR6 to irradiated breast cancer cells. These results suggest that radiation would improve the anti-tumor effect of NK cells through enhanced migration of NK cells to tumor site for the treatment of patients with breast cancer.

Transcriptional profile of tuberculosis antigen-specific T cells reveals novel multifunctional features.

In latent tuberculosis infection (LTBI) spread of the bacteria is contained by a persistent immune response, which includes CD4(+) T cells as important contributors. In this study we show that TB-specific CD4(+) T cells have a characteristic chemokine expression signature (CCR6(+)CXCR3(+)CCR4(-)), and that the overall number of these cells is significantly increased in LTBI donors compared with healthy subjects. We have comprehensively characterized the transcriptional signature of CCR6(+)CXCR3(+)CCR4(-) cells and found significant differences to conventional Th1, Th17, and Th2 cells, but no major changes between healthy and LTBI donors. CCR6(+)CXCR3(+)CCR4(-) cells display lineage-specific signatures of both Th1 and Th17 cells, but also have a unique gene expression program, including genes associated with susceptibility to TB, enhanced T cell activation, enhanced cell survival, and induction of a cytotoxic program akin to CTL cells. Overall, the gene expression signature of CCR6(+)CXCR3(+)CCR4(-) cells reveals characteristics important for controlling latent TB infections.

T cells home to the thymus and control infection.

The thymus is a target of multiple pathogens. How the immune system responds to thymic infection is largely unknown. Despite being considered an immune-privileged organ, we detect a mycobacteria-specific T cell response in the thymus following dissemination of Mycobacterium avium or Mycobacterium tuberculosis. This response includes proinflammatory cytokine production by mycobacteria-specific CD4(+) and CD8(+) T cells, which stimulates infected cells and controls bacterial growth in the thymus. Importantly, the responding T cells are mature peripheral T cells that recirculate back to the thymus. The recruitment of these cells is associated with an increased expression of Th1 chemokines and an enrichment of CXCR3(+) mycobacteria-specific T cells in the thymus. Finally, we demonstrate it is the mature T cells that home to the thymus that most efficiently control mycobacterial infection. Although the presence of mature T cells in the thymus has been recognized for some time, to our knowledge, these data are the first to show that T cell recirculation from the periphery to the thymus is a mechanism that allows the immune system to respond to thymic infection. Maintaining a functional thymic environment is essential to maintain T cell differentiation and prevent the emergence of central tolerance to the invading pathogens.

Neuroblastoma-derived TGF-ß1 modulates the chemokine receptor repertoire of human resting NK cells.

In this study, we show that neuroblastoma (NB) cell conditioning affects the chemokine receptor repertoire of human resting NK cells. In particular, NB cells upregulated the expression of CXCR4 and CXCR3 in all NK cells and downregulated CX3CR1 in the CD56(dim) subset. On the contrary, the expression of CXCR1 and CCR7 remained unaltered. The phenomenon was dependent on the release by NB cells of TGF-ß1, and rTGF-ß1 induced a chemokine receptor repertoire identical to that of NB-conditioned NK cells. The immune modulatory role of TGF-ß1 appears to be dose dependent because low amounts of the cytokine were sufficient to modulate CXCR4 and CX3CR1 expression, intermediate amounts modified that of CXCR3, and high amounts were necessary to downregulate the expression of the NKp30 activating receptor. Notably, a similar receptor modulation was observed in rTGF-ß2-conditioned NK cells. Finally, the analysis of NK cells from patients with stage 4 NB suggests that NB conditioning could exert in vivo an immune modulatory effect resembling that emerged from in vitro experiments. Altogether our data propose a novel tumor escape-mechanism based on the modulation of chemokine receptors that play pivotal roles in NK cells bone marrow homing, egress, or recruitment into peripheral tissues.

Distinct chemokine receptor axes regulate Th9 cell trafficking to allergic and autoimmune inflammatory sites.

Migration of Th cells to peripheral sites of inflammation is essential for execution of their effector function. The recently described Th9 subset characteristically produces IL-9 and has been implicated in both allergy and autoimmunity. Despite this, the migratory properties of Th9 cells remain enigmatic. In this study, we examined chemokine receptor usage by Th9 cells and demonstrate, in models of allergy and autoimmunity, that these cells express functional CCR3, CCR6, and CXCR3, chemokine receptors commonly associated with other, functionally opposed effector Th subsets. Most Th9 cells that express CCR3 also express CXCR3 and CCR6, and expression of these receptors appears to account for the recruitment of Th9 cells to disparate inflammatory sites. During allergic inflammation, Th9 cells use CCR3 and CCR6, but not CXCR3, to home to the peritoneal cavity, whereas Th9 homing to the CNS during experimental autoimmune encephalomyelitis involves CXCR3 and CCR6 but not CCR3. To our knowledge, these data provide the first insights into regulation of Th9 cell trafficking in allergy and autoimmunity.

Regulation of the development of the hepatic B cell compartment during Schistosoma mansoni infection.

During infection with the helminth parasite Schistosoma mansoni, Ab regulates hepatic inflammation, and local production of Ig in the liver appears to play a role in this process. Exploring the development of the B cell response during infection, we found that parasite-specific IgG1-secreting plasma cells appeared first in the hepatic and mesenteric lymph nodes (LNs) and then at later times in the spleen, liver, and bone marrow. The LN B cell population peaked between weeks 10 and 12 of infection, and then contracted at a time that coincided with the expansion of the hepatic IgG1(+) B cell compartment, suggesting that B cells migrate from LNs to liver. CXCL9 and -16 expression in the liver increased during the time frame of B cell recruitment. Expression of the CXCL16 receptor CXCR6 was increased on B cells within the hepatic LNs, but not the mesenteric LNs. CXCR3, the receptor for CXCL9, was broadly expressed on IgG1(+) B cells in LNs and liver during infection. Increased hepatic expression of CXCL9 and -16 failed to occur if the IL-10R was blocked in vivo, an intervention associated with decreased liver B cell infiltration and the development of severe disease. Hepatic LN IgG1(+) cells migrated toward CXCL9 and -16 in vitro and to the liver in a pertussis toxin-sensitive fashion. Our data suggest that the coordinated expression of CXCL9 and -16 in the liver and of CXCR6 and CXCR3 on responding B cells within the hepatic LNs underpins establishment of the hepatic B cell infiltrate during chronic schistosomiasis.

The molecular and functional characterization of clonally expanded CD8+ TCR BV T cells in eosinophilic granulomatosis with polyangiitis (EGPA).

In eosinophilic granulomatosis with polyangiitis (EGPA) clonally expanded T cells might concur in granuloma formation and vascular injury. The TCR ß-variable (BV) chain repertoire and third complementarity determining region (CDR3) of peripheral CD4+ and CD8+ cells in EGPA patients and age-matched controls and the expression of cytokines and chemokine receptors were investigated. The CD8+ lymphocytes of EGPA patients showed an increased frequency of BV expansions with a skewed profile of BV CDR3 lengths, increased CCR5 and CXCR3 expression and increased INFγ and TNFα production. In two patients, the TCR CDR3 cDNA sequences of the expanded BV family were identified. The CD4+ lymphocytes of EGPA patients revealed a higher expression of CRTH2 and increased production of IL-5. In conclusion, CD4+ T cells display a Th2 profile and CD8+ T cells are clonally expanded in EGPA and have a proinflammatory phenotype, suggesting their pathogenic role in vasculitic damage.

Tc17 cells mediate vaccine immunity against lethal fungal pneumonia in immune deficient hosts lacking CD4+ T cells.

Vaccines may help reduce the growing incidence of fungal infections in immune-suppressed patients. We have found that, even in the absence of CD4(+) T-cell help, vaccine-induced CD8(+) T cells persist and confer resistance against Blastomyces dermatitidis and Histoplasma capsulatum. Type 1 cytokines contribute to that resistance, but they also are dispensable. Although the role of T helper 17 cells in immunity to fungi is debated, IL-17 producing CD8(+) T cells (Tc17 cells) have not been investigated. Here, we show that Tc17 cells are indispensable in antifungal vaccine immunity in hosts lacking CD4(+) T cells. Tc17 cells are induced upon vaccination, recruited to the lung on pulmonary infection, and act non-redundantly in mediating protection in a manner that requires neutrophils. Tc17 cells did not influence type I immunity, nor did the lack of IL-12 signaling augment Tc17 cells, indicating a distinct lineage and function. IL-6 was required for Tc17 differentiation and immunity, but IL-1R1 and Dectin-1 signaling was unexpectedly dispensable. Tc17 cells expressed surface CXCR3 and CCR6, but only the latter was essential in recruitment to the lung. Although IL-17 producing T cells are believed to be short-lived, effector Tc17 cells expressed low levels of KLRG1 and high levels of the transcription factor TCF-1, predicting their long-term survival and stem-cell like behavior. Our work has implications for designing vaccines against fungal infections in immune suppressed patients.

Abnormal chemokine receptor profile on circulating T lymphocytes from nonallergic asthma patients.

BACKGROUND: T lymphocytes are involved in the pathogenesis of nonallergic asthma. The objective of this study was to characterize the subset distribution and pattern of chemokine receptor expression in circulating T lymphocyte subsets from nonallergic asthma patients. METHODS: Forty stable nonallergic asthma patients and 16 sex- and age-matched healthy donors were studied. Twelve patients did not receive inhaled steroids (untreated patients), 16 received 50-500 µg b.i.d. of inhaled fluticasone propionate (FP) (standard-dose patients), and 12 received over 500 µg b.i.d. of inhaled FP (high-dose patients) for at least 12 months prior to the beginning of this study and were clinically well controlled. Flow cytometry was performed using a panel of monoclonal antibodies (4 colors). RESULTS: Nonallergic asthma patients treated with high doses of inhaled FP showed a significant reduction in the percentages of CD3+ T lymphocytes compared to healthy controls. Untreated patients showed a significant increase in CCR6 expression in CD8+CD25+ and CD8+CD25+bright T cells compared to healthy controls. The results were similar for CXCR3 and CCR5 expression. In patients treated with standard doses of FP, CCR5 expression was significantly increased in CD3+ T lymphocytes relative to healthy controls. CONCLUSIONS: The different groups of clinically stable nonallergic asthmatic patients showed distinct patterns of alterations in subset distribution as well as CCR6, CXCR3, and CCR5 expression on circulating T lymphocytes. .