A dominant role for FcgammaRII in antibody-enhanced dengue virus infection of human mast cells and associated CCL5 release

Dengue virus is a major mosquito-borne human pathogen with four known serotypes. The presence of antidengue virus antibodies in the serum of individuals prior to dengue virus infection is believed to be an important risk factor for severe dengue virus disease as a result of the phenomenon of antibody-dependent enhancement operating on Fc receptor (FcR)-bearing cells. In addition to blood monocytes, mast cells are susceptible to antibody-enhanced dengue virus infection, producing a number of inflammatory mediators including IL-1, IL-6, and CCL5. Using the human mast cell-like lines KU812 and HMC-1 as well as primary cultures of human cord blood-derived mast cells (CBMC), we aimed to identify the participating FcRs in antibody-enhanced mast cell dengue virus infection, as FcRs represent a potential site for therapeutic intervention. CBMC expressed significant levels of FcgammaRI, FcgammaRII, and FcgammaRIII, and mast cell-like HMC-1 and KU812 cells expressed predominantly FcgammaRII. All four serotypes of dengue virus showed antibody-enhanced binding to KU812 cells. Specific FcgammaRII blockade with mAb IV.3 was found to significantly abrogate dengue virus binding to KU812 cells and CBMC in the presence of dengue-specific antibody. Dengue virus infection and the production of CCL5 by KU812 cells were also inhibited by FcgammaRII blockade.

Altered thymocyte migration during experimental acute Trypanosoma cruzi infection: combined role of fibronectin and the chemokines CXCL12 and CCL4

We previously showed migration disturbances in the thymus during experimental infection with Trypanosoma cruzi, the causative agent of Chagas disease. These changes were related to the enhanced expression of extracellular matrix ligands and receptors, leading to the escape of immature cells to the periphery. Here, we analyzed the expression and role of selected chemokines (CXCL12 and CCL4) and their receptors (CXCR4 and CCR5) in regulating thymocyte migration in conjunction with extracellular matrix during acute T. cruzi infection. We found increased chemokine deposition in the thymus of infected mice when compared to controls, accompanied by enhanced co-localization with fibronectin as well as up-regulated surface expression of CXCR4 and CCR5 in thymocytes. We also noticed altered thymocyte migration towards the chemokines analyzed. Such an enhancement was even more prominent when fibronectin was added as a haptotatic stimulus in combination with a given chemokine. Our findings suggest that thymocyte migration results from a combined action of chemokines and extracellular matrix (ECM), which can be altered during pathological conditions such as T. cruzi infection, and may be at the origin of the changes in the T cell repertoire seen in this pathological process.

Eosinophil-selective mediators in human strongyloidiasis

Strongyloides stercoralis infection is characterized by the production of IgE and eosinophils in peripheral blood. Experimental studies have demonstrated that eosinophils play an important role in protection against Strongyloides stercoralis, but the mechanisms regulating eosinophils are not known. In this study we have focused on analysing the molecules that selectively regulate eosinophil migration, namely eotaxin and interleukin-5 (IL-5), using an enzyme-linked immunosorbent assay in patients with strongyloidiasis. Serum expression of eotaxin and IL-5 were significantly increased in patients compared with the control group. This rise suggests that selective mediators of the eosinophil can have a role in immunity against S. stercoralis in human infection.

Analysis of Antitumor Activity Elicited by Vaccination with Combinations of Interleukin-12 DNA with gp100 DNA or the Chemokine CCL21In Vivo

The antitumor efficacy of human melanoma-associated antigen (hgp100) and chemokine CCL21 in combination with interleukin-12 (IL-12) was evaluated in a syngeneic melanoma mouse model. The rationale for this approach was based on previous studies showing that the efficacy of IL-12 therapy in melanoma patients correlated with the presence of antibodies against tumor-associated antigens. We have previously shown that application of xenogeneic human gp100 DNA (hgp100 DNA) is protective against mouse B16 melanoma. Furthermore, the chemokine CCL21 has the ability to chemoattract both dendritic cells (DCs) and T lymphocytes. We show here that intratumoral injection of IL-12-encoding DNA (IL-12 DNA) in combination with hgp100- encoding DNA (hgp100 DNA) into tumor-bearing mice led to a strong antitumor effect. Coapplication of IL- 12 DNA with CCL21-encoding DNA (CCL21 DNA) or recombinant CCL21 (recCCL21) protein also showed some efficacy. Triple therapy with IL-12 DNA, hgp100 DNA, and CCL21 DNA, however, showed less effect on tumor growth than double therapy with IL-12 DNA and hgp100 DNA. These findings open a new route of investigation of IL-12 and gp100 or other tumor-associated antigens in the immunotherapy of a variety of tumors.

Expression of CCL20 and granulocyte-macrophage colony-stimulating factor, but not Flt3-L, from modified vaccinia virus ankara enhances antiviral cellular and humoral immune responses

While modified vaccinia virus Ankara (MVA) is currently in clinical development as a safe vaccine against smallpox and heterologous infectious diseases, its immunogenicity is likely limited due to the inability of the virus to replicate productively in mammalian hosts. In light of recent data demonstrating that vaccinia viruses, including MVA, preferentially infect antigen-presenting cells (APCs) that play crucial roles in generating antiviral immunity, we hypothesized that expression of specific cytokines and chemokines that mediate APC recruitment and activation from recombinant MVA (rMVA) vectors would enhance the immunogenicity of these vectors. To test this hypothesis, we generated rMVAs that express murine granulocyte-macrophage colony-stimulating factor (mGM-CSF), human CCL20/human macrophage inflammatory protein 3alpha (hCCL20/hMIP-3alpha), or human fms-like tyrosine kinase 3 ligand (hFlt3-L), factors predicted to increase levels of dendritic cells (DCs), to recruit DCs to sites of immunization, or to promote maturation of DCs in vivo, respectively. These rMVAs also coexpress the well-characterized, immunodominant lymphocytic choriomeningitis virus nucleoprotein (NP) antigen that enabled sensitive and quantitative assessment of antigen-specific CD8(+) T-cell responses following immunization of BALB/c mice. Our results demonstrate that immunization of mice with rMVAs expressing mGM-CSF or hCCL20, but not hFlt3-L, results in two- to fourfold increases of cellular immune responses directed against vector-encoded antigens and 6- to 17-fold enhancements of MVA-specific antibody titers, compared to those responses elicited by nonadjuvanted rMVA. Of note, cytokine augmentation of cellular immune responses occurs when rMVAs are given as primary immunizations but not when they are used as booster immunizations, suggesting that these APC-modulating proteins, when used as poxvirus-encoded adjuvants, are more effective at stimulating naïve T-cell responses than in promoting recall of preexisting memory T-cell responses. Our results demonstrate that a strategy to express specific genetic adjuvants from rMVA vectors can be successfully applied to enhance the immunogenicity of MVA-based vaccines.

CCR6 and CCL20: Partners in Intestinal Immunity and Lymphorganogenesis

The CCR6 chemokine receptor is expressed by most B cells and subsets of T cells and dendritic cells (DCs) found in the gut mucosal immune system. CCL20, the single chemokine ligand for CCR6, is selectively made by the follicle-associated epithelium (FAE) overlying Peyer's patches (PPs) and isolated lymphoid follicles (ILFs). CCL20 contributes to the recruitment of CCR6-expressing B cells to these structures. CCL20 expression by the intestinal epithelium is also highly inducible in response to inflammatory stimuli. Thus, CCL20 functions as both an inflammatory and homeostatic chemokine. Interactions between CCR6 and CCL20 play a role at several stages in the development of intestinal lymphoid structures. A subset of the c-kit(+) lymphoid precursors found in cryptopatches (CPs) expresses CCR6. Recruitment of B cells to CPs and the subsequent expansion and organization of these B cells allows differentiation of some of these structures into ILFs. In CCR6 knockout mice, PPs are smaller with fewer follicles and the development of ILFs is compromised. These defects in the development of mucosal inductive sites in CCR6-deficient mice are responsible for decreased IgA production to oral antigens. CCR6 can be included with CXCR5 and CCR7 in a list of chemokine receptors that participate in shaping the organized lymphoid structures that are part of the intestinal immune system.

The role of chemokines in exercise-induced bronchoconstriction in asthma

BACKGROUND

The pathogenesis of exercise-induced bronchoconstriction in asthma is incompletely understood, and the role of chemokines has not been investigated.

OBJECTIVE

To investigate the involvement of the CC chemokines eotaxin, regulated upon activation normal T-cell expressed and secreted (RANTES), thymus and activation-regulated chemokine (TARC), and the CXC chemokine interferon-gamma-inducible protein 10 (IP-10) in exercise-induced bronchoconstriction.

METHODS

Four groups were enrolled: asthmatic children with positive (n = 15) and negative (n = 15) responses to exercise, children with cystic fibrosis (n = 14), and healthy children (n = 11). Levels of eotaxin, RANTES, TARC, and IP-10 were determined in plasma before, immediately after, and 6 and 24 hours after exercise challenge using enzyme-linked immunosorbent assay. Transcriptional activity was measured using reverse transcriptase-polymerase chain reaction.

RESULTS

Exercise did not induce any significant changes in systemic chemokine levels. A significant difference was observed only in the preexercise IP-10 levels among groups (P = .045). There was a significant difference in peripheral blood eosinophil counts among groups (P = .003). In asthmatic children with a positive response to exercise, there was an inverse correlation between eosinophil counts and eotaxin levels (r = -0.616; P = .01) and between forced expiratory volume in 1 second and TARC levels (r = -0.865; P = .001). Reverse transcriptase-polymerase chain reaction studies did not show any difference in the transcription of the chemokines.

CONCLUSIONS

Exercise does not cause any changes in the systemic expression of eosinophilic chemokines. Peripheral blood eosinophils may be a determinant of the exercise response, and eotaxin and TARC may be associated with eosinophil counts and forced expiratory volume in 1 second in children with a bronchoconstrictor response to exercise.

Cytokine expression patterns associated with systemic adverse events following smallpox immunization

Vaccinia virus is reactogenic in a significant number of vaccinees, with the most common adverse events being fever, lymphadenopathy, and rash. Although the inoculation is given in the skin, these adverse events suggest a robust systemic inflammatory response. To elucidate the cytokine response signature of systemic adverse events, we used a protein microarray technique to precisely quantitate 108 serum cytokines and chemokines in vaccine recipients before and 1 week after primary immunization with Aventis Pasteur smallpox vaccine. We studied 74 individuals after vaccination, of whom 22 experienced a systemic adverse event and 52 did not. The soluble factors most associated with adverse events were selected on the basis of voting among a committee of machine-learning methods and statistical procedures, and the selected cytokines were used to build a final decision-tree model. On the basis of changes in protein expression, we identified 6 cytokines that accurately discriminate between individuals on the basis of adverse event status: granulocyte colony-stimulating factor, stem cell factor, monokine induced by interferon-gamma (CXCL9), intercellular adhesion molecule-1, eotaxin, and tissue inhibitor of metalloproteinases-2. This cytokine signature is characteristic of particular inflammatory response pathways and suggests that the secretion of cytokines by fibroblasts plays a central role in systemic adverse events.

Similar functional activity of dendritic cells recruited to the mesenteric lymph nodes of newborn and adult mice after the rectal delivery of Mycobacterium bovis BCG

BCG rectal administration to newborn and adult mice induced protective immune responses against tuberculosis. BCG reaches the sub-epithelial site and the draining mesenteric lymph nodes (MLNs), and dendritic cells (DC) could be recruited to these sites. Using polarized Caco-2 epithelial cells, we showed that BCG translocates epithelial cells to basolateral compartment. Delayed in newborn BALB/c mice, an important recruitment of CD11c+ DCs, was documented in the rectal lamina propria and the MLNs during the first two weeks after rectal BCG delivery. In MLNs, two major DC subtypes were observed: conventional DCs (cDCs) (B220-) and plasmacytoid DCs (pDCs) (B220+). CIRE, mouse DC-specific intracellular adhesion molecule 3 grabbing non-integrin (DC-SIGN) is predominantly expressed on pDCs and at a higher level on pDCs from the adult compared to newborn MLNs. cDCs with a higher capacity to induce the proliferation of naïve CD4+ T cells than pDCs, triggered CD4+ T cells to produce interferon-gamma whereas pDCs triggered them to release interleukin-10. Both DC subtypes equilibrates T cells as a source of microbicidal/microbiostatic signals and those acting as source of counter-inflammatory signals, preventing tissue damage and/or accelerating tissue repair. Thus, rectal delivery of BCG could be a safe and efficient route of vaccination against tuberculosis.

Expression of TECK/CCL25 and MEC/CCL28 chemokines and their respective receptors CCR9 and CCR10 in porcine mucosal tissues

CCL25 and CCL28 (also named TECK and MEC) are CC chemokines primarily expressed by thymic dendritic cells and mucosal epithelial cells. The cognate receptors of CCL25 and CCL28, named CCR9 and CCR10, are mainly expressed on T lymphocytes for CCR9 and IgA(+) and IgM(+) plasmablasts for CCR9 and CCR10, respectively. In human and mouse, chemokines CCL25 and CCL28 play an important role in attracting immune cells to the gastrointestinal tract and in controlling segmental specialization of the intestinal immune system. To investigate if CCL25 and CCL28 play a similar role in the pig and to better understand lymphocyte trafficking in this species, we cloned porcine CCL25 and CCR10 and measured expression of CCL25, CCL28, CCR9, and CCR10 transcripts by real-time and conventional PCR in various tissues from newborn and young piglets, and adult sows. The results of the expression analyses show that (i) expression of CCL25 mRNA is mainly restricted to the small intestine, (ii) CCL28 mRNA expression is detectable in all tested epithelial mucosal surfaces with the highest levels of expression in the mammary gland, trachea and large intestine, (iii) high levels of expression of CCR9 mRNA in CD3+ T lymphocytes, gut-associated lymphoid tissues (GALT), and the small intestine, (iv) high levels of expression of CCR10 mRNA in GALT, the large intestine, the small intestine, and the mammary gland, and (v) up-regulation of CCL28 mRNA expression during lactation in the mammary gland. This pattern of expression, which is discussed in the context of compartmentalization of the porcine common mucosal immune system into upper aero-digestive tract, small intestine and large intestine, suggests a key role for CCL28 in the recruitment of IgA secreting cells into the mammary gland enabling the passive transfer of IgA antibodies from mother to infant.

A possible role for CCL27/CTACK-CCR10 interaction in recruiting CD4 T cells to skin in human graft-versus-host disease

Graft-versus-host disease (GvHD) is a serious complication of allogeneic stem cell transplantation (SCT) affecting the skin, gut and liver. The involvement of distinct organs suggests a role for tissue-specific chemokines and their receptors in directing activated donor T cells to these sites. In this study the potential involvement of the skin-specific CCL27/CTACK-CCR10 interaction was investigated in 15 paediatric SCT patients with skin GvHD. During the course of skin GvHD, peripheral blood T cells from these patients contained a high proportion of CD4+ CCR10+ T cells that disappeared after the GvHD was resolved. These cells were CD45RO+, expressed additional skin homing markers (cutaneous lymphocyte-associated antigen and CCR4), and produced the T-cell helper type 1-cytokines tumour necrosis factor-alpha and interleukin-2. The increase in CD4+ CCR10+ T cells was absent in SCT patients without GvHD. Immunohistochemical investigations showed CD4+ CCR10+ T cells in the GvHD skin biopsies of the same patients, but not in the gut biopsies of patients also suffering from gut GvHD. The infiltration of CD4+ CCR10+ T cells in the GvHD-affected skin correlated with an enhanced epidermal expression of CCL27/CTACK, the ligand for CCR10. These findings support the involvement of CCL27/CTACK-CCR10 interaction in recruiting CD4+ T cells to the skin, thus contributing to the pathogenesis of acute GvHD.

Redundant role of chemokines CCL25/TECK and CCL28/MEC in IgA+ plasmablast recruitment to the intestinal lamina propria after rotavirus infection

Rotaviruses (RV) are the most important cause of severe childhood diarrheal disease. In suckling mice, infection with RV results in an increase in total and virus-specific IgA(+) plasmablasts in the small intestinal lamina propria (LP) soon after infection, providing a unique opportunity to study the mechanism of IgA(+) cell recruitment into the small intestine. In this study, we show that the increase in total and RV-specific IgA(+) plasmablasts in the LP after RV infection can be blocked by the combined administration of Abs against chemokines CCL25 and CCL28, but not by the administration of either Ab alone. RV infection in CCR9 knockout mice still induced a significant accumulation of IgA(+) plasmablasts in the LP, which was blocked by the addition of anti-CCL28 Ab, confirming the synergistic role of CCL25 and CCL28. The absence of IgA(+) plasmablast accumulation in LP following combined anti-chemokine treatment was not due to changes in proliferation or apoptosis in these cells. We also found that coadministration of anti-CCL25 and anti-CCL28 Abs with the addition of anti-alpha(4) Ab did not further inhibit IgA(+) cell accumulation in the LP and that the CCL25 receptor, CCR9, was coexpressed with the intestinal homing receptor alpha(4)beta(7) on IgA(+) plasmablasts. Finally, we showed that RV infection was associated with an increase in both CCL25 and CCL28 in the small intestine. Hence, our findings indicate that alpha(4)beta(7) along with either CCR9 or CCR10 are sufficient for mediating the intestinal migration of IgA(+) plasmablasts during RV infection.

CCR5 usage by CCL5 induces a selective leukocyte recruitment in human skin xenografts in vivo

CCR5 is one of the major inflammatory chemokine receptors with potential therapeutical applications in humans. However, the redundancy of chemokines and their receptors, and the species specificity of chemokine receptor antagonists pose challenges to understanding of the role they play in pharmacological situations. To address this question, we used a humanized severe combined immunodeficient mouse model grafted with human skin and autologous leukocytes, and evaluated the effect of a blocking antibody against human CCR5, on CCL5-induced cutaneous leukocyte recruitment in vivo. At baseline, CCL5 induced a significant recruitment of T cells mainly of the memory phenotype, of monocytes/macrophages, eosinophils, and IFN-gamma(+) but not IL-4(+) and IL-5(+) cells. In vivo, anti-CCR5 antibody was able to almost completely inhibit the recruitment of monocytes/macrophages and T-helper (Th)1-type cells to inhibit partially the attraction of memory T cells, but had no effect on eosinophil infiltration, although all these cell types express other CCL5 binding chemokine receptors than CCR5. These results indicate that the in vivo environment regulates target cell specificity of CCL5 leading to differential cell recruitment, suggesting that antagonizing CCR5 receptor may be of therapeutic value in diseases such as acquired immuno deficiency syndrome, where CCL5/CCR5, monocytes, and Th1-type cells play a predominant role.

The Role of Platelet-Derived Growth Factor Receptor in Eotaxin Signaling of Eosinophils

BACKGROUND

Receptor tyrosine kinases (RTKs) such as epidermal growth factor receptor (EGFR) and platelet-derived growth factor receptor (PDGFR) are capable of eliciting kinase activity after ligand binding. In several cells, RTKs are activated via the G-protein-coupled receptor independent of the ligand-RTK interaction. We have previously found that EGFR is transactivated via CC chemokine receptor 3 in bronchial epithelial cells and that this pathway is important for mitogen-activated protein (MAP) kinase activation and cytokine production. It has recently been suggested that hypereosinophilic syndrome results from the fusion tyrosine kinase FIP1L1-PDGFRA. Although it is possible that the PDGFR signal is involved in eosinophil function, the details are still unclear.

METHODS

Blood eosinophils were purified using Percoll and anti-CD16 antibody-coated magnetic beads. Expression of PDGFR mRNA was examined by RT-PCR. After stimulating eosinophils with eotaxin, the phosphorylation of MAP kinases was examined by Western blotting with the antiphosphospecific MAP kinase antibody. The eotaxin-induced eosinophil chemotaxis was studied using Boyden chambers.

RESULTS

Eosinophils expressed PDGFRbeta mRNA in 4 out of 8 donors, while PDGFRalpha mRNA was expressed in only 1 donor. Protein expression of PDGFR was also detectable in eosinophils from some donors. AG1295, a specific inhibitor of PDGFR, showed dose-dependent inhibition of eotaxin-induced MAP kinase phosphorylation in the eosinophils expressing PDGFRbeta mRNA. The chemotaxis of these eosinophils was significantly inhibited by AG1295 (n = 3).

CONCLUSIONS

Our results suggest that PDGFR modifies the CCR3-MAP kinase signaling pathway and chemotactic response in some donors. The pharmacological targeting of PDGFR may be a new strategy to treat eosinophilic disorders.

A genetic basis for human susceptibility to West Nile virus

West Nile virus (WNV) infects thousands of humans annually and causes a spectrum of disease ranging from an acute febrile illness to lethal encephalitis. A new study suggests a link between CCR5Delta32 (a common mutant allele of the chemokine and HIV receptor CCR5) and fatal WNV infection. The study highlights a possible risk in targeting this receptor for the prevention and/or treatment of infectious diseases.

Effects of Salmonella enterica serovars Typhimurium (ST) and Choleraesuis (SC) on chemokine and cytokine expression in swine ileum and jejunal epithelial cells

The gastrointestinal epithelium represents a barrier to potentially invasive enteric pathogens, maintains a role in innate immune surveillance, and is a source of both chemokine and cytokine chemotactic mediators in response to bacterial invasion. In the current study, we evaluated cytokine and chemokine mediators known to regulate movement of macrophages (macrophage migration inhibitory factor; MIF), neutrophils (IL8), dendritic cells (CCL20), and epithelial remodeling (osteopontin; OPN) in response to invasive swine enteropathogens Salmonella enterica serovar Typhimurium (ST) or Choleraesuis (SC). For the in vivo experiment, weaned pigs served as uninfected controls (0 h) or were given 3 x 10(9) CFU ST orally. Pigs were sacrificed at 8, 24, 48, and 144 h after inoculation and total RNA was extracted from defined segments of proximal (PI) and distal (DI) ileum. Relative expression of MIF and OPN were not affected by ST. IL8 expression was increased numerically (P = 0.17 for the interaction term) at 24 and 144 h in the PI and these increases accounted for greater expression in the PI relative to the DI (P < 0.05). Relative expression of CCL20 was increased at 24 h after ST (P < 0.05). Next, we evaluated the time course of MIF, IL8, CCL20, and OPN mRNA expression induced by application of lipopolysaccharide (LPS), ST or SC in vitro using pig jejunal epithelial cells (IPEC-J2). Cells were grown to confluency on permeable membranes, and treated apically with LPS (10 ng/mL), ST or SC (10(8)/well). After 1 h, cells were washed to remove LPS or extracellular bacteria, and media containing gentamicin was added to kill remaining extracellular bacteria. Media and RNA were collected at 1.5, 3, and 6 h after treatment. MIF mRNA was not affected by LPS or bacterial treatment. Similarly, IL8 expression was not affected by LPS, but was increased by ST and SC relative to controls at 1.5 and 3 h post exposure (P < 0.05 for all comparisons). Treatment with SC increased CCL20 mRNA relative to controls at 3 h (P < 0.05), while ST increased CCL20 at 1.5, 3, and 6h with maximal expression at 6 h (P < 0.05 for all comparisons). ST and SC increased polarized IL8 secretion. Our data demonstrate that invasive bacterial pathogens in the pig gastrointestinal tract trigger upregulation of selected cytokine and chemokine mediators, but serovars of Salmonella elicited differing patterns of activation in vitro.

Specific recruitment of CC chemokine receptor 4-positive regulatory T cells in Hodgkin lymphoma fosters immune privilege

Hodgkin lymphoma (HL) is characterized by the presence of a small number of tumor cells in a rich background of inflammatory cells, but the contribution of the abundant nontumor cells to HL pathogenesis is poorly understood. We showed that migratory CD4(+) cells induced by HL cells were hyporesponsive to T-cell receptor stimulation and suppressed the activation/proliferation of the effector CD4(+) T cells in an autologous setting. We further showed that HL cells in the affected lymph nodes were surrounded by a large number of lymphocytes expressing both CC chemokine receptor 4 (CCR4) and FOXP3. These findings indicate that the migratory cells induced by HL cells function as regulatory T (Treg) cells so that these cells create a favorable environment for the tumor cells to escape from host immune system. In addition, we showed that a chimeric anti-CCR4 monoclonal antibody (mAb) could deplete CCR4(+) T cells and inhibit the migration of CD4(+)CD25(+) T cells in vitro. Recognition of the importance of CCR4(+) Treg cells in the pathogenesis of HL will allow rational design of more effective treatments, such as use of an anti-CCR4 mAb, to overcome the suppressive effect of CCR4(+) Treg cells on the host immune response to tumor cells.

CCL27 is a critical factor for the development of atopic dermatitis in the keratin-14 IL-4 transgenic mouse model

The keratin-14 IL-4 transgenic (Tg) mouse model of atopic dermatitis (AD) is characterized by skin infiltration of T cells, early up-regulation of T(h)2 cytokines and late surge of T(h)1 cytokines. In the present study, we investigated the role of CCL27, a T cell skin-homing chemokine known to be elevated in sera of human AD patients, in disease development in our animal model of AD. The results showed that the mRNA and protein levels of CCL27 in the skin and serum were significantly increased in IL-4 Tg mice. The percentage of T cells expressing CCR10 in skin draining lymph nodes of IL-4 Tg mice was increased, consistent with the findings of >80% of skin-infiltrating T cells in Tg mice expressing CCR10. Chemotaxis transmigration assay demonstrated that CCL27 promotes a greater degree of migration of T cells in diseased Tg mice. Subcutaneous injection of neutralizing anti-CCL27 to IL-4 Tg mice with early skin lesions resulted in reduced clinical progression of inflammation, accompanied with decreased T cell and mast cell infiltration in the skin, and down-regulation of inflammatory cytokines. In conclusion, CCL27 and CCR10 interaction is important for the development of skin inflammation in our AD model.

CCL19 reduces tumour burden in a model of advanced lung cancer

Epstein–Barr virus-induced molecule 1 ligand chemokine (CCL19) is a CC chemokine that chemoattracts both dendritic cells (DC) and T lymphocytes. We evaluated the antitumour efficacy of CCL19 in a murine model of spontaneous bronchoalveolar cell carcinoma. These transgenic mice (CC-10 TAg) express the SV40 large T antigen under the Clara Cell promoter, develop bilateral, multifocal, pulmonary carcinomas and die at 4 months owing to progressive pulmonary tumour burden. To mimic therapy in late-stage disease, 3-month-old transgenic mice were treated with recombinant CCL19 (0.5 μg dose⁻¹) by intranodal (axillary lymph node region) injection three times per week for 4 weeks. CCL19 treatment led to a marked reduction in tumour burden with extensive mononuclear infiltration of the tumours compared to diluent treated controls. Flow cytometric analyses showed significant increases in CD4 and CD8T cell subsets as well as DC in the lungs of CCL19-treated mice. Lung tissue cytokine profiles showed a shift towards immune stimulatory molecules with a decrease in the immunosuppressive cytokine TGF-β. Our findings show that CCL19 may serve as a potential immune stimulator and provide a strong rationale for the evaluation of CCL19 in cancer immunotherapy.

Endothelial and epithelial expression of eotaxin-2 (CCL24) in nasal polyps

BACKGROUND

Nasal polyposis is mostly associated with eosinophilia of mucosal tissue. This points to the implication of CC chemokines in nasal eosinophilia. Recently the CC chemokine eotaxin-2 (CCL24) was identified. This study was initiated to localize the cellular source, analyze expression of mRNA, and quantify protein synthesis of CCL24.

METHODS

Specimens of nasal inferior turbinates from controls and polypous tissue from patients suffering from chronic polypous sinusitis were collected. Furthermore, fibroblasts and epithelial cells were cultured. CCL24 protein was analyzed by immunohistochemistry and ELISA, expression of mRNA by SQ-RT-PCR.

RESULTS

CCL24 was observed in endothelial and epithelial cells. Specimens from patients expressed significantly (>2fold) more CCL24 mRNA than controls. Fibroblasts and unstimulated cells did not express CCL24 mRNA. Upon stimulation with TNF-alpha, INF-gamma, IL-4, or costimulation with TNF-alpha and INF-gamma CCL24 mRNA was significantly enhanced (3.2-19.6%). In controls, fibroblast, and unstimulated cells CCL24 protein was below detection limit. Most polyps comprised significant amounts of CCL24 (mean 0.24 ng/mg). TNF-alpha, INF-gamma or IL-4 induced CCL24 protein (0.1-0.3 ng/ml) in epithelial cells. Costimulation with TNF-alpha and IL-4 (0.1-30 and 1-30 ng/ml, respectively) synergistically induced synthesis of CCL24 protein (0.18-0.31 ng/ml).

CONCLUSION

In nasal polyps endothelial and epithelial cells are obviously the main source of CCL24, which was shown for transcription (mRNA) and production (protein) levels and was associated with diseases. Results gave evidence of CLL24- directed migration of cells from inside (the bloodstream) to the epithelial side (mucosa) in eosinophilic inflammatory diseases, e.g. nasal polyposis.

Intrapulmonary administration of CCL21 gene-modified dendritic cells reduces tumor burden in spontaneous murine bronchoalveolar cell carcinoma

The antitumor efficiency of dendritic cells transduced with an adenovirus vector expressing secondary lymphoid chemokine (CCL21) was evaluated in a murine model of spontaneous bronchoalveolar cell carcinoma. The transgenic mice (CC-10 TAg) express the SV40 large T antigen (TAg) under the Clara cell promoter, develop bilateral, multifocal, and pulmonary adenocarcinomas, and die at 4 months as a result of progressive pulmonary tumor burden. A single intratracheal administration of CCL21 gene-modified dendritic cells (DC-AdCCL21) led to a marked reduction in tumor burden with extensive mononuclear cell infiltration of the tumors. The reduction in tumor burden was accompanied by the enhanced elaboration of type 1 cytokines [IFN-gamma, interleukin (IL)-12, and granulocyte macrophage colony-stimulating factor] and antiangiogenic chemokines (CXCL9 and CXCL10) but a concomitant decrease in the immunosuppressive molecules (IL-10, transforming growth factor-beta, prostaglandin E(2)) in the tumor microenvironment. The DC-AdCCL21 therapy group revealed a significantly greater frequency of tumor-specific T cells releasing IFN-gamma compared with the controls. Continuous therapy with weekly intranasal delivery of DC-AdCCL21 significantly prolonged median survival by >7 weeks in CC-10 TAg mice. Both innate natural killer and specific T-cell antitumor responses significantly increased following DC-AdCCL21 therapy. Significant reduction in tumor burden in a model in which tumors develop in an organ-specific manner provides a strong rationale for further evaluation of intrapulmonary-administered DC-AdCCL21 in regulation of tumor immunity and genetic immunotherapy for lung cancer.

Effects of steroid treatment on lung CC chemokines, apoptosis and transepithelial cell clearance during development and resolution of allergic airway inflammation

BACKGROUND

Steroid treatment of allergic eosinophilic airway diseases is considered to attenuate cell recruitment by inhibiting several chemokines and to cause eosinophil clearance through inducement of apoptosis of these cells. However, roles of these mechanisms in the actions of steroids in vivo have not been fully established. Also, as regards clearance of tissue eosinophils other mechanisms than apoptosis may operate in vivo.

OBJECTIVE

This study explores anti-inflammatory effects of steroids instituted during either development or resolution of airway allergic inflammation.

METHODS

Immunized mice were subjected to week-long daily allergen challenges (ovalbumin). Steroid treatment was instituted either amidst the challenges or exclusively post-allergen challenge. CC chemokines, goblet cell hyperplasia, occurrence of eosinophil apoptosis, and airway tissue as well as lumen eosinophilia were examined at different time-points.

RESULTS

Daily steroids instituted amid the allergen challenges non-selectively attenuated a range of chemokines, permitted egression of tissue eosinophils into airway lumen to increase, and reduced development of lung tissue eosinophilia. Steroid treatment instituted post-challenge selectively inhibited the CC-chemokine regulation upon activation, normal T cell expressed and secrted (RANTES), permitted continued egression of eosinophils into airway lumen, and resolved the tissue eosinophilia. Eosinophil apoptosis rarely occurred at development and resolution of the allergic eosinophilic inflammation whether the animals were steroid treated or not. However, anti-Fas monoclonal antibodies given to mice with established eosinophilia post-challenge produced apoptosis of the tissue eosinophils indicating that apoptotic eosinophils, if they occur, are well detectible in vivo.

CONCLUSION

Airway tissue eosinophils are likely eliminated through egression into airway lumen with little involvement of apoptosis and phagocytosis. Our data further suggest that therapeutic steroids may resolve airway inflammation by permitting clearance of tissue eosinophils through egression and inhibiting RANTES-dependent cell recruitment to lung tissues.

A multistep adhesion cascade for lymphoid progenitor cell homing to the thymus

Homing of bone marrow (BM)-derived progenitors to the thymus is essential for T cell development. We have previously reported that two subpopulations of common lymphoid progenitors, CLP-1 and CLP-2, coexist in the BM and give rise to lymphocytes. We demonstrate that CLP-2 migrate to the thymus more efficiently than any other BM-derived progenitors. Short-term adoptive transfer experiments revealed that CLP-2 homing involves P-selectin/P-selectin glycoprotein ligand 1 interactions, pertussis toxin-sensitive chemoattractant signaling by CC chemokine ligand 25 through CC chemokine receptor 9, and binding of the integrins alpha4beta1 and alphaLbeta2 to their respective ligands, vascular cell adhesion molecule 1 and intercellular adhesion molecule 1. Preferential thymus-tropism of CLP-2 correlated with higher chemokine receptor 9 expression than on other BM progenitors. Thus, CLP access to the thymus is controlled by a tissue-specific and subset-selective multistep adhesion cascade.

Chemokines enhance immunity by guiding naive CD8+ T cells to sites of CD4+ T cell-dendritic cell interaction

CD8+ T cells have a crucial role in resistance to pathogens and can kill malignant cells; however, some critical functions of these lymphocytes depend on helper activity provided by a distinct population of CD4+ T cells. Cooperation between these lymphocyte subsets involves recognition of antigens co-presented by the same dendritic cell, but the frequencies of such antigen-bearing cells early in an infection and of the relevant naive T cells are both low. This suggests that an active mechanism facilitates the necessary cell-cell associations. Here we demonstrate that after immunization but before antigen recognition, naive CD8+ T cells in immunogen-draining lymph nodes upregulate the chemokine receptor CCR5, permitting these cells to be attracted to sites of antigen-specific dendritic cell-CD4+ T cell interaction where the cognate chemokines CCL3 and CCL4 (also known as MIP-1alpha and MIP-1beta) are produced. Interference with this actively guided recruitment markedly reduces the ability of CD4+ T cells to promote memory CD8+ T-cell generation, indicating that an orchestrated series of differentiation events drives nonrandom cell-cell interactions within lymph nodes, optimizing CD8+ T-cell immune responses involving the few antigen-specific precursors present in the naive repertoire.

Potential role of CCL27 and CCR10 expression in melanoma progression and immune escape

Aim of this study was to investigate using immunohistochemistry techniques the interrelation between T immunoreactive cells and the expression of CCR10 and its ligand CCL27 in 59 cutaneous melanocytic lesions. In malignant melanomas, T lymphocyte density was significantly decreased from thin melanomas to intermediate and thick ones (P<0.0005). CCR10 expression was found both in benign and malignant lesions and it was directly correlated with the Breslow depth (P=0.0298) and inversely with T lymphocyte density (P=0.0231). Moreover, cases with positive sentinel lymph node tended to have a higher CCR10 expression compared to cases with negative sentinel lymph node (P=0.0281). When CCR10 and CCL27 expression were evaluated together, CCR10-/CCL27-melanomas tended to have a higher mean density of CD3+ and CD8+ lymphocytes. Our results suggest that in human melanomas CCR10 and CCL27 may act to increase the ability of neoplastic cells to grow, invade tissue, disseminate to lymph nodes and to escape the host immune response.

Aberrant expression of CC and CXC chemokines and their receptors in patients with asthma

This study further elucidates the roles of selected chemokines (IP-10, MIG, and RANTES) and their receptors (CCR3, CCR5, and CXCR3) in asthma. We compared their profiles in six groups of participants-atopic cohort and nonatopic cohort (each including controls and asthmatic patients with or without steroid therapy). Plasma concentration of IP-10 was significantly lower while that of RANTES and the expression of CCR3 were higher in asthmatic patients (all p < 0.05). Plasma RANTES correlated positively with the GINA severity score in all asthmatic patients (r=0.27, p < 0.05), and with IL-13 in nonatopic asthmatic patients (r=0.46, p < 0.05). In asthmatic patients, the ex vivo release of IP-10 and MIG was attenuated in PBMC activated with allergen, mitogens and IL-18 (p < 0.05). In conclusion, plasma RANTES may be a surrogate marker for asthma and the diminished Th1 related CXC chemokine production may contribute to Th2 predominance in asthma.

Mature monocyte-derived dendritic cells respond more strongly to CCL19 than to CXCL12: consequences for directional migration

The chemokine receptor CCR7 is crucial for migration of mature dendritic cells (DC) directed toward secondary lymphoid organs; however, there is little knowledge about the function of the homeostatic chemokine receptor CXCR4 in DC and its contribution to directional migration of DC during inflammation. By comparing the impact of chemokine receptor engagement on mature DC we found that the CCR7 ligand CCL19 holds a stronger chemotactic potency than the CXCR4 ligand CXCL12. Moreover, CCL19 elicited rapid, steep and long-lasting mobilization of intracellular calcium in individual cells and induced intense phosphorylation of extracellular signal-regulated kinase 1/2 and protein kinase B, while the intracellular signals elicited by CXCL12 were in part distinct and significantly weaker. Analysis of chemokine receptor expression revealed that although CCR7 and CXCR4 were expressed by a similar percentage of DC, the mean fluorescence intensity of CCR7 was up to six times higher, suggesting a higher receptor density. Based on these correlations we propose that the type of chemokine signal in conjunction with the expression and functional activity of the respective chemokine receptor is also determining the migration rate and potency of a chemotactic response in mature DC. In conclusion, our data support the fundamental role of CCR7 for rapidly guiding DC toward secondary lymphoid organs at an extra- and intracellular molecular level and on the contrary render CXCR4 a weaker contributor to directional migration of DC during inflammation.

Novel roles of osteopontin and CXC chemokine ligand 7 in the defence against mycobacterial infection

Granulocyte-macrophage colony-stimulating factor (GM-CSF)-induced human monocyte-derived macrophage (GM-Mphi) or macrophage CSF (M-CSF)-induced human monocyte-derived Mphi (M-Mphi) are distinct in terms of the resistance to Mycobacterium tuberculosis. To elucidate the role of molecules involved in the functional differences between these Mphis, we investigated the gene expression profiles using microarray. After culture of CD14+ monocytes with CSFs, Mphis were cultured with or without bacillus Calmette-Guérin (BCG) (GM-Mphi-BCG and M-Mphi-BCG). The gene expression profiles from these cells were compared. Chemokines highly expressed in M-Mphis were selected and evaluated for anti-mycobacterial activity and superoxide production. FN1 and FCGR2B were the most up-regulated genes in GM-Mphi and M-Mphi, respectively. After stimulation with BCG, three chemokine genes (Osteopontin (SPP1), CXC chemokine ligand 7 (CXCL7) and CC chemokine ligand 11 (CCL11)) were highly expressed in M-Mphi-BCG when compared to those in GM-Mphi-BCG. A significantly increased resistance to M. tuberculosis H37Ra was observed after the stimulation of GM-Mphi with SPP1 or CXCL7. Superoxide production levels of SPP1- or CXCL7-stimulated GM-Mphis were higher than those of GM-Mphis without stimulation. These results indicate that both SPP1 and CXCL7 might have a role in the resistance against mycobacteria, at least in part, through augmenting reactive oxygen intermediate production in Mphis.

RANTES, MDC and SDF-1α, prevent the HIVgp120-induced food and water intake decrease in rats

Human immunodeficiency virus (HIV)-wasting syndrome might be facilitated by the HIVgp120 affecting the immunological system. We studied the effect (subchronic administration: 5 days) of HIVgp120, and a few immune-response mediators: regulated upon activation normal T-cell expressed and presumably secreted (RANTES), stromal derived factor-1alpha (SDF-1alpha), macrophage-derived chemokine (MDC), and their combination, on food and water intake in rats, motor control and pain perception. Eighty male adult Wistar rats received an intracerebroventricular (icv) administration of: vehicle 5 microl/day or 0.92 nmol daily of HIVgp120IIIB, RANTES, SDF-1alpha, or MDC, and the combination of RANTES+HIVgp120IIIB, SDF-1alpha+HIVgp120IIIB, or MDC+HIVgp120IIIB. Food and water intake was measured every day during administration, and 24 and 48 h after the last administration. Rats were also weighed the first and the last day of experiment in order to detect the impact of these treatments in the body weight. HIVgp120IIIB significantly decreased food and water intake. These rats gain less weight than the control (vehicle) and chemokines-treated subjects with exception of those treated with SDF-1alpha that also gain less weight. In addition, HIVgp120 deteriorated motor control. HIVgp120IIIB effects on food and water intake, and motor control were prevented by these chemokines. HIVgp120+RANTES, HIVgp120+SDF-1alpha, and SDF-1alpha alone induced hyperalgesia. Results suggest an interaction between HIVgp120 and the chemokine system to generate the HIV-wasting syndrome, the motor abnormalities and changes in pain perception.

Multinucleate giant cells and the control of chemokine secretion in response to Mycobacterium tuberculosis

Multinucleate giant cells (MGC) are characteristic of tuberculous granulomas, but their function is not well understood. In a comparative study, we investigated regulation of chemokine secretion by MGC generated using 5 microg/ml ConA and 1000 IU/ml IFN-gamma. After 72-h differentiation of MGC cultures, CXCL8, CCL2 and CCL3 concentrations were 9540+/-110 pg/ml, 11190+/-2210 pg/ml and 19440+/-440 pg/ml respectively all significantly higher than in MDM (P<0.01). There was associated increased chemokine gene expression. M.tb stimulation of MGC, MDM and monocytes increased CXCL8 secretion. M.tb increased monocyte CCL2 secretion, whereas MGC and MDM secreted CCL2 constitutively. CXCL10 secretion was induced in M.tb-stimulated MDM and constitutive in MGC. All cell types responded to M.tb with CCL3 secretion. Monocyte chemokine secretion was associated with increased gene expression, whereas M.tb-stimulated MGC principally upregulated CCL3 gene expression. In summary, differentiating MGC express genes for and secrete chemokines which regulate cell influx to sites of infection. Established MGC will contribute to cell recruitment to granuloma, but this may not depend on exposure to the pathogen.

Propolis extracts exhibit an immunoregulatory activity in an OVA-sensitized airway inflammatory animal model

Propolis, which has been used widely in folk medicine, has been shown to exhibit various biological activities but its immunoregulatory and anti-inflammatory activities in intact animals have not been well studied. We investigated these activities of propolis using an ovalbumin-induced asthma animal model. Mice were immunized and sensitized by exposure to ovalbumin (OVA) antigen and administered with low- (65 mg/kg body weight) and high-dose (325 mg/kg body weight) propolis water extracts by tube feeding. The serum OVA-specific IgE titer and cytokine profiles in cultured splenocytes and bronchoalveolar lavage fluids (BALF) were analyzed. The number of eosinophils in BALF was counted. Here we demonstrate that propolis extracts can suppress the serum levels of OVA-specific IgE and IgG(1), and airway hyperresponsiveness (AHR) in OVA-sensitized mice. There are no significant differences in the concentration of eotaxin or the number of eosinophils in BALF among the four groups. However, the higher dose of propolis extracts decreases the level of IL-5 in BALF. The splenocytes from mice administered with propolis extracts (low- and high-dose groups) exhibit a strong inhibition of IL-10 secretion and up-regulation of IFN-gamma secretion in splenocytes stimulated with concanavalin A (ConA). In addition, cytokine (IFN-gamma, IL-6, and IL-10) secretion in OVA-stimulated splenocytes from the propolis groups was significantly lower than that in the control group. These results suggest that propolis extracts may be a potential novel therapeutic agent for asthma.

CD56brightCD16(-) NK cells accumulate in psoriatic skin in response to CXCL10 and CCL5 and exacerbate skin inflammation

Psoriasis is an immune-mediated skin disease characterized by lymphocytic infiltration and altered keratinocyte differentiation. Using immunohistochemical techniques we found that the cellular infiltrate in acute psoriatic plaques includes 5-8% CD3(-)CD56(+) natural killer (NK) cells, mostly localized in the mid and papillary dermis. NK lymphocytes isolated from punch biopsy specimens of psoriatic plaques showed a CD56(bright)CD16(-)CD158b(-) phenotype, failed to express the skin homing cutaneous lymphocyte-associated antigen and released abundant IFN-gamma upon stimulation. Supernatants from psoriatic NK cells induced MHC class II and ICAM-1 expression and release of CXCL10 and CCL5 by cultured psoriatic keratinocytes. Skin NK cells expressed high levels of the chemokines receptors CXCR3 and CCR5, intermediate amounts of CXCR1, CCR6 and CCR8, and low levels of CCR1, CCR2, CCR4, CCR7 and CX3CR1. In addition, they promptly migrated in vitro toward CXCL10, CCL5, supernatants of IFN-gamma-activated psoriatic keratinocytes and, to a lower extent, CCL20 and CCL4. In contrast, they failed to migrate toward CXCL8, CCL1, CCL2, CCL3, CCL17, CCL19 and CX3CL1. Taken together, our results implicate NK lymphocytes as newly identified protagonists in the pathogenesis of psoriasis. Their distinctive homing properties should be taken into account in the design of specific therapy aimed at blocking pathogenic cell accumulation in the skin.

Chemotactic responses of IL-4-, IL-10-, and IFN-gamma-producing CD4+ T cells depend on tissue origin and microbial stimulus

Th1- and Th2-polarized immune responses are crucial in the defense against pathogens but can also promote autoimmunity and allergy. The chemokine receptors CXCR3 and CCR4 have been implicated in differential trafficking of IFN-gamma- and IL-4-producing T cells, respectively, but also in tissue and inflammation-specific homing independent of cytokine responses. Here, we tested whether CD4+ T cells isolated from murine tissues under homeostatic or inflammatory conditions exhibit restricted patterns of chemotactic responses that correlate with their production of IFN-gamma, IL-4, or IL-10. In uninfected mice, IL-4-producing T cells preferentially migrated to the CCR4 ligand, CCL17, whereas IFN-gamma-expressing T cells as well as populations of IL-4+ or IL-10+ T cells migrated to the CXCR3 ligand, CXCL9. All cytokine-producing T cell subsets strongly migrated to the CXCR4 ligand, CXCL12. We assessed chemotaxis of T cells isolated from mice infected with influenza A virus or the nematode Nippostrongylus brasiliensis, which induce a strong Th1 or Th2 response in the lung, respectively. Unexpectedly, the chemotactic responses of IL-4+ T cells and T cells expressing the immunosuppressive cytokine IL-10 were influenced not only by the strongly Th1- or Th2-polarized environments but also by their anatomical localization, i.e., lung or spleen. In contrast, IFN-gamma+ T cells exhibited robust chemotaxis toward CXCL9 and had the most consistent migration pattern in both infection models. The results support a model in which the trafficking responses of many effector and regulatory T cells are regulated as a function of the infectious and tissue environments.

IL-17E upregulates the expression of proinflammatory cytokines in lung fibroblasts

BACKGROUND

IL-17E is a new TH2 cytokine that promotes airway eosinophilia in mice. IL-17E proinflammatory activity has been proposed to involve induction of cytokine and chemokine production. Recruitment of inflammatory cells may be mediated by tissue-resident cells.

OBJECTIVE

This study aimed to evaluate whether fibroblasts represent a target of IL-17E for the production of eosinophil active mediators in the lung.

METHODS

Expression of IL-17B receptor (IL-17BR), a receptor for IL-17E, was evaluated by immunofluorescent staining, Western blot, and real-time PCR in human primary lung fibroblasts. Mediator production was analyzed by using real-time PCR and ELISA after stimulation of fibroblasts with IL-17E alone or in combination with TNF-alpha and TGF-beta1. Expression of IL-17E and of eosinophil major basic protein was evaluated by immunohistochemistry in bronchial biopsies from subjects with asthma.

RESULTS

Human primary lung fibroblasts constitutively expressed IL-17BR. IL-17BR mRNA levels were increased in cells stimulated with TNF-alpha and decreased with TGF-beta1. IL-17E slightly upregulated CC chemokine ligand (CCL)-5, CCL-11, GM-CSF, and CXC chemokine ligand (CXCL)-8 mRNA in fibroblasts. Moreover, IL-17E and TNF-alpha synergistically induced GM-CSF and CXCL-8 mRNA. IL-17E also potentiated the upregulation of CXCL-8 transcripts observed with TGF-beta1. In contrast, TGF-beta1 decreased IL-17E-induced CCL-11 mRNA. The capacity of IL-17E to enhance GM-CSF and CXCL-8 responses to TNF-alpha was accompanied by production and secretion of both proteins by lung fibroblasts. Finally, IL-17E was detected in asthma in eosinophil-infiltrated bronchial submucosa.

CONCLUSION

IL-17E may contribute to the induction and maintenance of eosinophilic inflammation in the airways by acting on lung fibroblasts. This study supports a role for IL-17E in asthma pathophysiology.

CCL5 Modulates Pneumococcal Immunity and Carriage

Understanding the requirements for protection against pneumococcal carriage and pneumonia will greatly benefit efforts in controlling these diseases. Recently, it has been shown that genetic polymorphisms can result in diminished expression of CCL5, which results in increased susceptibility to and progression of infectious diseases. We show that CCL5, together with Th cytokine mRNA expression, is temporally up-regulated during pneumococcal carriage. To determine the contribution of CCL5 to pneumococcal surface antigen A-specific humoral and cellular pneumococcal immunity, mice were treated with anti-CCL5 or control Abs before and during Streptococcus pneumoniae strain EF3030-challenge for the initiation of carriage. CCL5 blockade resulted in a decrease of CD4(+) and CD8(+) T cells as well as CD11b(+) cells in the spleen, cervical lymph node, lung, and nasopharyngeal associated lymphoid tissue during the recognition phase of the pneumococcal adaptive immune response. CCL5 blockade significantly reduced the Ag-specific IgG2a and IgG1 Abs in serum and IgA Ab levels in nasal washes. These decreases also corresponded to reductions in Ag-specific T cell (mucosal and systemic) responses. CCL5 inhibition resulted in decreasing the quantity of IL-4- and IFN-gamma-secreting CD4(+) T cells and increasing the number of Ag-specific IL-10-producing CD4(+) T cells; these changes combined also corresponded with the transition from pneumococcal carriage to lethal pneumonia. These data suggest that CCL5 is an essential factor for the induction and maintenance of protective pneumococcal immunity.

Modulation of murine experimental asthma by Ascaris suum components

BACKGROUND

We have recently isolated two distinct components from Ascaris suum adult worms with different effects on the immune system: the allergenic protein of A. suum (APAS-3), which induces IgE antibody production, and suppressive protein of A. suum (PAS-1), which inhibits humoral and cellular immune responses induced by unrelated antigens. In this study, we investigated the immunomodulatory effect of PAS-1 on a murine model of asthma induced by APAS-3.

METHODS

BALB/c mice were immunized twice with APAS-3 or APAS-3 plus PAS-1 by the intraperitoneal and subcutaneous route (on days 0 and 7) and challenged twice with the same antigens intranasally (days 14 and 21). Two days after the last challenge, the allergic airway inflammation was evaluated by cellular migration, eosinophil peroxidase (EPO) activity, cytokine and chemokine production and pulmonary mechanical parameters.

RESULTS

The allergenic properties of APAS-3 were confirmed by the stimulation of anaphylactic IgE and IgG1 antibody production and eosinophilic airway inflammation and hyper-responsiveness. On the other hand, PAS-1-treated mice showed a marked suppression of cellular migration and EPO activity that correlated well with a significant reduction in the levels of IL-4, IL-5, eotaxin and RANTES in the bronchoalveolar lavage (BAL) fluid. In contrast, considerable amounts of IL-10 were observed in the BAL fluid of PAS-1-treated mice. Airway hyper-responsiveness was obtained in APAS-3-immunized mice, but the conductance of the respiratory system was restored to normal values in the presence of PAS-1.

CONCLUSION

These results indicate that A. suum allergenic protein APAS-3 induces a T helper 2-type immune response and, consequently, eosinophilic airway inflammation and hyper-responsiveness. Moreover, the modulatory protein PAS-1 has a marked suppressive effect on this response, and the inhibition of cytokine (IL-4, IL-5) and chemokine (eotaxin and RANTES) release, probably because of the presence of IL-10, may contribute to this effect.

Coordinate expression of CC chemokine ligand 5, granulysin, and perforin in CD8+ T cells provides a host defense mechanism against Mycobacterium tuberculosis

The ability of CD8+ T cells to kill intracellular pathogens depends upon their capacity to attract infected cells as well as their secretion of cytolytic and antimicrobial effector molecules. We examined the Ag-induced expression of three immune effector molecules contained within cytoplasmic granules of human CD8+ T cells: the chemokine CCL5, the cytolytic molecule perforin, and the antimicrobial protein granulysin. Macrophages infected with virulent Mycobacterium tuberculosis triggered the expression of CCL5 in CD8+ T cells only in donors with previous exposure to the tuberculosis bacteria, not in naive donors. Functionally, CCL5 efficiently attracted M. tuberculosis-infected macrophages, but failed to exert direct antibacterial activity. Infected macrophages also triggered the expression of granulysin in CD8+ T cells, and granulysin was found to be highly active against drug-susceptible and drug-resistant M. tuberculosis clinical isolates. The vast majority of CCL5-positive cells coexpressed granulysin and perforin. Taken together, this report provides evidence that a subset of CD8+ T cells coordinately expresses CCL5, perforin and granulysin, thereby providing a host mechanism to attract M. tuberculosis-infected macrophages and kill the intracellular pathogen.

Preferential targeting of CD4-CCR5 complexes with bifunctional inhibitors: a novel approach to block HIV-1 infection

Two receptors, CD4 and one of several chemokine receptors, are required for cellular HIV-1 infection, with CCR5 being the main coreceptor for macrophage-tropic strains. We have designed bifunctional fusion proteins, consisting of RANTES/CCL5 and a single-chain Fv Ab fragment against CD4 to simultaneously block CD4 and CCR5. The fusion proteins bind to both receptors, compete with RANTES/CCL5 binding, and induce down-modulation of CCR5 approximately 10 times more efficiently on CD4+ compared with CD8+ T cells. Moreover, after short incubation and subsequent washout, a significant down-modulation of CCR5 was only seen with the fusion proteins and only on CD4+ cells, but not with unmodified RANTES or on CD4- cells, indicating a preferential targeting of CCR5 on CD4+ T cells. The fusion proteins block M-tropic HIV infection more efficiently than RANTES/CCL5 and CD4 Abs alone or in combination. To our knowledge this is the first report of simultaneous blockade of an HIV-1 receptor and coreceptor with bifunctional inhibitors.

Helicobacter pylori activates NF-kappaB via the alternative pathway in B lymphocytes

Helicobacter pylori causes various gastroduodenal diseases including gastric MALT lymphoma, but the mechanism underlying H. pylori-induced carcinogenesis is not known. The alternative pathway for NF-kappaB activation, which involves the processing of NF-kappaB2/p100 to p52, has been implicated in lymphocyte survival, attenuated apoptosis, and secondary lymphoid tissue development. In this study, we investigated H. pylori-induced activation of NF-kappaB through the alternative pathway in B lymphocytes. In immunoblot and EMSA, H. pylori induced NF-kappaB2/p100 processing to p52 and subsequent nuclear accumulation in IM-9 (human B cell line) cells and human peripheral blood B cells, but not in AGS (human gastric cancer cell line) cells. The activation of the alternative pathway was LPS-dependent but not cag pathogenicity island-dependent. Alternative pathway activation by H. pylori was associated with attenuated apoptosis. The expression levels of B lymphocyte chemoattractant, EBI-1 ligand chemokine, and stromal cell-derived factor-1alpha mRNAs were up-regulated in cocultured human B cells and in infected human gastric mucosa. In the infected mucosa, NF-kappaB2/p100 and p52 were detected immunohistochemically in the cytoplasm and nuclear compartments of lymphocytes, but not in epithelial cells. In summary, H. pylori activates the alternative NF-kappaB pathway in B lymphocytes. The effects on chemokine production and antiapoptosis mediated by H. pylori-induced processing of NF-kappaB2/p100 to p52 may drive lymphocytes to acquire malignant potential.

CCL5-enhanced human immature dendritic cell migration through the basement membrane in vitro depends on matrix metalloproteinase-9

The proinflammatory chemokine CC chemokine ligand 5 (CCL5) is a potent chemoattractant of immature dendritic cells (iDCs). It remains to be elucidated whether CCL5 may also enhance iDC migration through the basement membrane by affecting matrix metalloproteinase (MMP)-9 secretion. In this study, iDCs were differentiated in vitro from human monocytes of healthy donors. Zymographic analysis of cellular membranes of nontreated iDCs revealed a basal secretion of the pro- and active MMP-9, whereas only pro-MMP-9 was detected in conditioned media. Increasing concentrations of CCL5 significantly enhanced MMP-9 secretion by iDCs, peaking at 100 ng/ml, which optimally increased iDC migration through a reconstituted basement membrane (Matrigel) in vitro. The CCL5-enhanced secretion of MMP-9 occurred early (2 h) and was maintained at least for 10 h. A significant increase in MMP-9 mRNA synthesis was detected by reverse transcriptase-polymerase chain reaction, only at 6 h of CCL5 treatment, which suggests that the early effect of CCL5 (0-4 h) on MMP-9 secretion was independent of mRNA synthesis, whereas the more delayed effect (6-10 h) could be mediated through an increase in MMP-9 gene expression. In a Matrigel migration assay, the CCL5-enhanced iDC migration was reduced significantly by specific inhibitors of MMP-9, such as tissue inhibitor of metalloproteinase-1 or an anti-MMP-9 antibody, which indicates that iDC migration through the basement membrane depends on MMP-9. These results suggest that under inflammatory conditions, the chemokine CCL5 may enhance iDC migration through the basement membrane by rapidly increasing their MMP-9 secretion.

Characterization of 23 CC chemokine genes and analysis of their expression in channel catfish (Ictalurus punctatus)

Chemokines are a large family of chemotactic cytokines playing crucial roles in the innate immune response. CC chemokines constitute the largest subfamily of chemokines, with 28 CC chemokines identified from mammalian species. However, the status of CC chemokines in teleosts is yet to be determined. We previously identified 26 catfish CC chemokine cDNAs from catfish. In this study, we isolated and sequenced 23 channel catfish CC chemokine genes amounting to a total of over 56 kb of genomic sequences. Genomic organization of the 23 CC chemokine genes was determined by comparing the generated genomic sequences with the previously identified cDNA sequences. Microsatellites were identified from 16 catfish CC chemokine genes allowing them to be utilized for genome mapping. Structural analysis indicated conservation of genomic organization of CC chemokine genes, which may facilitate the establishment of orthologies. Expression of all known catfish CC chemokine transcripts was assessed in nine important tissues. Of the 26 catfish CC chemokine genes, 14 were universally expressed, six were widely expressed in many tissues, while six were highly tissue-specific.

[Evaluation of individual vulnerability to HIV infection of health care employees--hope or reality?]

Due to the increasing number of infections with hepatitis viruses and HIV, world wide as well as among the health care workers, the prevention of occupationally acquired infections in the operating room environment becomes crucial. Three plausible strategies do not require any knowledge of the exact mechanisms of exposure: vaccination, impenetrable protective barriers and post exposure prophylaxis. This paper presents the opinion on individual risks of HIV infections based on genetic factors. It has been proved that one of the CCR5 gene varient for chemokine receptor is related with resistance to HIV-1 infection. Similary, the level of cytokine depends on the number of gene CCL3L1 copy and it influences susceptibility to HIV-1 infection and AIDS development.

Inhibition of human immunodeficiency virus-1 (HIV-1) by beta-chemokine analogues in mononuclear cells from HIV-1-infected patients with active tuberculosis

Tuberculosis (TB) enhances human immunodeficiency virus-1 (HIV-1) activity in patients with dual HIV-1/TB infection. Therapies that control augmentations of HIV-1 activity at sites of Mycobacterium tuberculosis (MTB) infection may be useful in inhibition of viral expansion. Regulated upon activation, normal T-cell expressed and secreted (RANTES) analogues (AOP and NNY) are potent in inhibiting the entry of primary HIV-1 isolates into host mononuclear cells. These analogues were used to inhibit MTB-induced HIV-1 entry in blood monunuclear cells (PBMC) from patients with pulmonary TB, and pleural fluid mononuclear cells (PFMC) from patients with pleural TB. PBMC or PFMC were cultured with and without MTB in presence and absence of RANTES analogues. HIV-1 strong stop DNA was assessed by real-time polymerase chain reaction (PCR) as a measure of infection. CCR5 mRNA was assessed by real-time reverse transcription (RT)-PCR and by immunostaining and FACS analysis. HIV-1 infection was induced by MTB in vitro in PBMC from the majority (14 of 20) of HIV-1/TB subjects, and new infection was inhibited by AOP- or NNY-RANTES. HIV-1 infection was also inhibited by these reagents in MTB-induced PFMC from three of three patients with pleural TB. Expression of CCR5 mRNA was significantly induced by MTB in PBMC from patients with pulmonary TB. Further, expression of CCR5 was higher in PFMC compared to PBMC from patients with pleural TB. Also, CCR5 was fourfold higher on CD14(+) pleural mononuclear cells than on CD4(+) lymphocytes. Blocking new HIV-1 infection of mononuclear cells may be useful in control of HIV-1 during dual HIV-1/TB infection.

Immunosuppressive effects of CCL17 on pulmonary antifungal responses during pulmonary invasive aspergillosis

Aspergillus fumigatus-sensitized CCR4-deficient (CCR4-/-) mice exhibit an accelerated clearance of conidia during fungal asthma. In the present study, we examined the roles of CCL17 and CCL22, two CCR4 ligands, during pulmonary invasive aspergillosis in neutropenic mice. Kaplan-Meier survival curve analysis revealed that wild-type C57BL/6 (CCR4+/+) mice were significantly protected from the lethal effects of Aspergillus compared with their wild-type controls following systemic neutralization with anti-CCL17 but not anti-CCL22 antibodies. Systemic neutralization of CCL17 significantly increased whole-lung CCL2 levels. Mouse survival and histological analysis revealed that the receptor mediating the deleterious effects of CCL17 was CCR4 since mice genetically deficit in CCR4 (CCR4-/-) did not develop invasive aspergillosis. Enzyme-linked immunosorbent assay analysis of whole-lung samples at day 2 after conidial challenge in neutrophil-depleted CCR4-/- and CCR4+/+ mice revealed that whole-lung IL-12 levels were significantly increased in the CCR4-/- group compared with the wild-type group. Also at day 2 after conidial challenge, significantly greater numbers of CD11c+ F4/80+ and CD11c+/CD86+ but fewer CD3/NK1.1+ cells were present in the lungs of CCR4-/- mice compared with their wild-type counterparts. Thus, CCL17-CCR4 interactions dramatically impair the pulmonary antifungal response against A. fumigatus in neutropenic mice.

Detection of altered secondary lymphoid-tissue chemkine responsiveness in Balb/c mice infected with Schistosoma mansoni

To determine the extent to which Balb/c mice splenic T cells were affected by S. mansoni infection, this study aims to investigate the ability of the T cells to produce interferon (IFN)-&, and their chemotactic ability at 7 weeks post-infection. The splenic T cells were capable of producing levels of IFN-& comparable with splenic T cells from naive mice. However, the T cells exhibited altered chemotactic activity, as evidenced by an inability to respond to secondary lymphoid-tissue chemokine (SLC/CCL21). Although no difference in chemokine expression was found between the spleens of infected versus control mice, chemokine production was greater in the livers of infected versus control mice. Collectively, these data indicate that Balb/c mice with 7-wk S. mansoni infection possess splenic T cells with altered chemotactic activity and that the alterations may be a consequence of granulomatous response in the liver.

Increased expression of chemokines in the skin of chronic proliferative dermatitis mutant mice

Chemokines direct the migration of leukocytes to sites of inflammation and are potential targets for anti-inflammatory therapy. Chronic proliferative dermatitis (cpdm/cpdm) mutant mice develop a persistent eosinophilic dermatitis associated with increased T(H)2 cytokines in the skin. Expression patterns of chemokines in the skin of cpdm/cpdm mice were evaluated to define the mechanisms driving cutaneous infiltration by leukocytes. RNA isolated from the skin of mutant and littermate control mice revealed a significant increase in Ccl1 (TCA-3), Ccl2 (MCP-1), Ccl11 (eotaxin), Ccl17 (TARC), Cxcl10 (IP-10), and the chemokine receptor Ccr3. The concentration of CCL11 protein was increased two- to threefold in the skin of cpdm/cpdm mice by enzyme-linked immunosorbent assay. In vitro culture of primary dermal fibroblasts from cpdm/cpdm and control mice with tumor necrosis factor, IL-4, and IL-13 stimulation did not reveal differences in their ability to secrete CCL11, suggesting that the increased chemokine expression observed in the skin of cpdm/cpdm mice is most likely caused by the increased T(H)2 cytokines in the dermis of this mouse model. Treatment of cpdm/cpdm mice with CCL11-neutralizing polyclonal antibodies did not affect the number of eosinophils in the skin or the severity of the dermatitis. Neutralizing multiple chemokines or chemokine receptors may be necessary to decrease eosinophil accumulation. The cpdm/cpdm mutant mouse is a potentially useful model to determine the role of various chemokines in eosinophil accumulation in chronic inflammation.

Macrophage activation switching: an asset for the resolution of inflammation

Macrophages play a central role in inflammation and host defence against microorganisms, but they also participate actively in the resolution of inflammation after alternative activation. However, it is not known whether the resolution of inflammation requires alternative activation of new resting monocytes/macrophages or if proinflammatory activated macrophages have the capacity to switch their activation towards anti-inflammation. In order to answer this question, we first characterized differential human macrophage activation phenotypes. We found that CD163 and CD206 exhibited mutually exclusive induction patterns after stimulation by a panel of anti-inflammatory molecules, whereas CCL18 showed a third, overlapping, pattern. Hence, alternative activation is not a single process, but provides a variety of different cell populations. The capacity of macrophages to switch from one activation state to another was then assessed by determining the reversibility of CD163 and CD206 expression and of CCL18 and CCL3 production. We found that every activation state was rapidly and fully reversible, suggesting that a given cell may participate sequentially in both the induction and the resolution of inflammation. These findings may provide new insight into the inflammatory process as well as new fields of investigation for immunotherapy in the fields of chronic inflammatory diseases and cancer.

T Cell-Regulated Neutrophilic Inflammation in Autoinflammatory Diseases

Previous studies of acute generalized exanthematous pustulosis, a peculiar drug hypersensitivity reaction, suggested that CXCL8-producing T cells regulate sterile, polymorphonuclear neutrophil-rich skin inflammations. In this study, we test the hypothesis of whether CXCL8-producing T cells are present in autoinflammatory diseases like pustular psoriasis and Behçet's disease. Immunohistochemistry of normal skin revealed few CD4+ and CD8+ T cells, few CXCL8+ cells, and no neutrophilic infiltration, whereas in acute exacerbations of atopic dermatitis, numerous CD4+ T cells but few CD8+ T cells, neutrophils, or CXCL8+ cells were detected. In contrast, a pronounced infiltration of neutrophils and of predominantly CD4+ T cells was observed in skin biopsies from pustular psoriasis, Behçet's disease, and acute generalized exanthematous pustulosis, with infiltrating T cells strongly positive for CXCL8 and the chemokine receptor CCR6. Skin-derived T cell clones from pustular skin reactions were positive for CCR6 but negative for CCR8 and secreted high amounts of CXCL8 and GM-CSF, often together with IFN-gamma and TNF-alpha after in vitro stimulation. Moreover, some skin-derived T cell clones from Behçet's disease and from pustular psoriasis predominantly produced CXCL8 and GM-CSF, but failed to secrete IL-5 and IFN-gamma. These cells might represent a particular subset as they differ from both Th1 as well as Th2 T cells and are associated with a unique, neutrophil-rich sterile inflammation. Our findings suggest that CXCL8/GM-CSF-producing T cells may orchestrate neutrophil-rich pathologies of chronic autoinflammatory diseases like pustular psoriasis and Behçet's disease.