3; for methods see supplementary information) Thus,

3; for methods see supplementary information). Thus, find protocol mutations in genes that lead to mutator phenotypes in P. aeruginosa can enhance microcolony initiation and growth during biofilm culture. This different architecture of

the biofilm formed by mutator strains has an impact on the tolerance of the biofilms to antibiotics. We found that the PAO1 ∆mutT had increased tolerance to piperacillin/tazobactam compared with the wild-type (Fig. 4). It has been shown in planktonic growth that under piperacillin/tazobactam selective pressure PAO1 ∆mutT developed a larger resistant subpopulation compared with PAO1 and that the mechanism of resistance was related to increased beta-lactamase production (Mandsberg et al., 2009). Selection of such a resistant subpopulation during treatment of the biofilm might explain the increased tolerance to piperacillin/tazobactam INCB024360 in vitro of PAO1 ∆mutT compared with PAO1. It has been shown recently that theoretically optimized PK/PD parameters failed to suppress resistance development in biofilm-grown bacteria. The antibiotic concentration that prevents the selection of resistant mutants (mutant preventive concentration) is increased in biofilms compared with planktonic growth due to the particular physiology and architecture of biofilms favouring gradual mutational

resistance development, especially in mutator strains (Macia et al., 2011). The increased tolerance to piperacillin/tazobactam of PAO1 ∆mutT might also be due to a more efficient SOS response in mutators. We have recently shown in another mutant that is unable to repair DNA oxidative

lesions that such unrepaired lesions trigger an oxidative stress response in P. aeruginosa (Mandsberg et al., 2011) that could trigger an SOS response and better survival in the presence of antibiotics. Hyperproduction of beta-lactamase (Ciofu et al., 1994; Bagge et al., 2002) and overexpresison of efflux-pumps (Jalal et al., 2000; Islam et al., 2009) are the most common mechanisms of resistance encountered in CF P. aeruginosa isolates. Due to the selective pressure exerted by maintenance antibiotic treatment, occurrence of resistant P. aeruginosa strains during chronic airway infection in CF is common, and the next most important mechanism of resistance to beta-lactam antibiotics is overproduction of the chromosomally encoded beta-lactamase (Giwercman et al., 1990; Ciofu, 2003). In biofilms of P. aeruginosa that overproduce beta-lactamase, the presence in the biofilm matrix of beta-lactamases will lead to hydrolysis of the beta-lactam antibiotics before they reach the bacterial cells. Nichols et al. (1989) predicted from mathematical models that bacteria expressing high levels of chromosomal beta-lactamase growing in biofilms would be exposed to reduced concentrations of beta-lactam antibiotics due to accumulation of the enzyme in the polysaccharide matrix.

136 A20-silenced DC showed spontaneous and enhanced expression

136 A20-silenced DC showed spontaneous and enhanced expression

of co-stimulatory molecules and pro-inflammatory cytokines and had different effects on T-cell subsets: they inhibited Treg cells and hyperactivated tumour-infiltrating cytotoxic T lymphocytes and T helper cells that produced IL-6 and TNF-α and were refractory to Treg-cell-mediated suppression. Mechanistic studies revealed that A20 regulated DC production of retinoic acid and pro-inflammatory cytokines, inhibiting the expression of gut-homing receptors on T and B cells. Their work provided a strategy for the development of an efficient vaccination.137 When compared with other cell types, DC are not easily transduced by adenoviruses, requiring high multiplicities of infection to obtain expression selleck screening library of antigen in most cells. Pereboev et al.138 High Content Screening have reported that CFm40L, an adapter molecule combining the coxsackie-adenovirus receptor fused to the ecto-domain of CD40L by way of a trimerization motif, was able to efficiently target adenoviruses to DC. Moreover, direct immunization with adenoviral particles coated with this adapter molecule was able to induce stronger immune responses than uncoated adenoviral particles. In their studies, targeting of an adenovirus encoding HCV NS3 protein (AdNS3)

to DC with CFm40L strongly enhanced NS3 presentation in vitro, activating IFN-γ-producing T cells. Immunization of mice with these DC promoted strong CD4 and CD8 T-cell responses against HCV NS3. CFh40L, Fossariinae a similar adapter molecule containing human CD40L, enhanced transduction and maturation of human MDDC from patients with chronic HCV infection and healthy

donors revealed similar maturation levels. DC transduced with AdNS3 and the adapter molecule CFm/h40L exhibit enhanced immunostimulatory functions, induced robust anti-HCV NS3 immunity in animals, and can induce antiviral immune responses in subjects with chronic HCV infection. This strategy may serve as therapeutic vaccination for patients with chronic hepatitis C.31 To determine whether T-cell responses induced by the protein vaccines could be enhanced after boosting with a viral vector, non-human primates were boosted with a replication defective, recombinant New York vaccinia virus (NYVAC)-HIV Gag/Pol/Nef vector. Boosting with recombinant NYVAC strongly enhances IFN-γ-producing T cells following priming with DEC-HIV Gag p24 or HIV Gag p24 plus Poly ICLC. The NYVAC boosting generates multifunctional CD4+ and CD8+ cytokine-producing T cells with a similar breadth to those elicited by protein priming. Hence, a robust, broad, durable and polyfunctional CD4+ and CD8+ T-cell response is generated by boosting a relatively low frequency of cross-primed CD8+ T cells induced by a protein vaccine with a single immunization with NYVAC-HIV Gag/Pol/Nef.

Activated glia have been shown to be both necessary and sufficien

Activated glia have been shown to be both necessary and sufficient for enhanced nociception [13]. Specifically, microglia activation is one of the most common

and earliest features of most neuroinflammatory disorders [15,16] and CNS pathologies [17–19]. We have reported increased activation of astrocytes and microglia in spinal cord tissue of a CRPS patient when compared to control tissue [20]. In man, CNS microglia is thought to arise during gestation from mesodermal/mesenchymal sources [21]. Normally, CNS microglia can replenish with little or no need of repopulation from circulating bone marrow-derived progenitors [21]. However, in disease conditions, blood-derived GDC-0068 manufacturer monocytes/macrophages are recruited into the CNS and differentiate into microglia [22,23]. A recent study demonstrated that, following nerve injury, blood monocytes/macrophages infiltrate the CNS and differentiate into functional microglia PI3K inhibitor at the involved segmental spinal level, resulting in hypersensitivity and chronic pain [24]. Human peripheral blood monocytes can be subdivided into two subgroups based on their expression of cell surface markers: one expressing CD14, but not CD16 (CD14+CD16-) and the other expressing both CD14 and CD16 (CD14+CD16+) [25]. Both subgroups produce similar levels of proinflammatory cytokines. However, CD14+CD16+

monocytes produce much lower levels of the anti-inflammatory cytokine interleukin (IL)-10, suggesting that these cells constitute a proinflammatory subtype [26]. Increased proportions of the CD14+CD16+ subgroup have been described in disease states including sepsis, acquired immunodeficiency disease syndrome, rheumatoid arthritis, systemic lupus erythematosus and active sarcoidosis [25,27–30]. The primary aim of this study was to evaluate Oxymatrine the proportion of proinflammatory CD14+CD16+ monocytes as well as the levels of several plasma cytokines in blood from patients afflicted with CRPS compared to age- and gender-matched healthy control individuals. All subjects were enrolled after giving informed consent as approved by the Drexel University College

of Medicine Institutional Review Board (IRB). CRPS patients were recruited from the pain clinic of Drexel University School of Medicine and fulfilled the International Association for the Study of Pain (IASP) diagnostic criteria for CRPS [31]. Healthy control subjects were recruited from the general public. The exclusion criteria for all subjects included: pregnancy, recent infection, lupus erythematosus, HIV/AIDS, rheumatoid arthritis, recent extracorporeal circulation (haemodialysis, bypass surgery, plasmapheresis), bone marrow transplant, immunosuppressive therapy, blood disorders (anaemia, leukaemia), thymectomy or sarcoidosis. All CRPS patients received a complete neurological examination and pain evaluation.

Moreover, we and others have shown that γδ T lymphocytes migrate

Moreover, we and others have shown that γδ T lymphocytes migrate in vitro toward CCL25, via its counterpart receptor CCR9 [[11, 15]]; however, the role of the CCL25/CCR9 pathway in γδ T-cell migration has not been described.

Chemokine-mediated check details T-lymphocyte migration into the tissue is a multistep process that requires the action of adhesion molecules. This large group of cell-surface proteins is responsible for cell rolling, firm adhesion, and transendothelial migration. Firm adhesion is achieved by the interaction of leukocyte integrins with their endothelial counter ligands. CCL25 has been shown to induce lymphocyte adhesion to VCAM-1 and MadCAM-1, mediated by α4β1 and α4β7 integrins [[16, 17]]. The coexpression of CCR9 and α4β7 integrin has been described on gut-associated T lymphocytes and has been shown to dictate T-cell adhesion and migration to inflamed intestinal mucosa [[18-21]]. γδ T lymphocytes also express both α4β1 and α4β7 integrins that mediate the in vitro adhesion to cytokine-activated endothelial cells [[22-24]].

In the present study, we demonstrate Inhibitor Library research buy that CCL25/CCR9 is involved in the migration of γδ T cells via the α4β7 integrin to inflamed tissue during an allergic reaction. In addition, we show that CCL25 modulates IL-17 levels by inducing the specific migration of CCR6+/IL-17+ γδ T lymphocytes. The intrapleural (i.pl.) injection of recombinant mouse CCL25 (rmCCL25) into C57BL/6 mice induced the pleural accumulation of γδ T lymphocytes (SAL 4.3 versus CCL25 Alanine-glyoxylate transaminase 7.0% in CD3+ T lymphocytes), with no observation of changes in the numbers of αβ T lymphocytes (Fig. 1A and B) or other leukocyte populations (not shown) 24 h after stimulation. γδ T cells recovered from CCL25-stimulated

pleura expressed CCR9 and α4β7 integrin, both phenotype markers of gut mucosal lymphocytes (Fig. 1C). It is noteworthy that, even though only approximately 40% of pleural γδ T cells from i.pl. CCL25-stimulated mice were CCR9+ (Fig. 1C), this amount corresponds to the larger portion of newly arrived γδ T cells (Fig. 1A). The analysis of activation marker expression revealed that i.pl. rmCCL25 stimulation triggered the accumulation of CD2hi and CD25+ γδ T lymphocytes (Fig. 1C). However, no significant differences were observed in the migration of CD45RB+, CD69+, and CD122+ γδ T cells recovered from CCL25-stimulated and from nonstimulated mice. The i.pl. antigenic challenge with ovalbumin (OVA) into immunized mice induced increased levels of CCL25 in pleural washes recovered within 24 h (Fig. 2A). CCL25 has been shown to be mainly produced by epithelial cells [[25]]. Considering that the mesothelium is an epithelial-like cell lining that covers the pleural surface, which actively synthesizes inflammatory mediators, we investigated the production of CCL25 by mesothelial cells.

NKRs were first described as surface receptors on NK cells that b

NKRs were first described as surface receptors on NK cells that bind to specific HLA class I molecules (4). Upon binding to their respective ligands, the receptors transmit inhibitory or activating intracellular signals. Many of these inhibitory and activating receptors have been identified. NKG2D, NKG2A, and KIR3DL1 are three of RAD001 cost the most prevalent NKRs and play important roles in a variety of cellular functions (5). NKG2D and NKG2A are both members of the C-type

lectin NKR family. NKG2D is a key member of an array of receptors that can activate or co-stimulate NK cells, while NKG2A recognizes non-classical HLA-E molecules and inhibits the function of NK cells (6–7). Meanwhile, KIR3DL1 is one of the KIRs from the immunoglobulin-like superfamily. This SCH727965 molecular weight receptor binds to HLA-B and HLA-A allotypes bearing the HLA-Bw4 serospecificity and delivers inhibitory signals (8). Since their discovery on NK cells, NKR expression has also been detected on T cells. Although both CD4+ and CD8+αβT cells can express NKRs, expression is much more common on CD8+αβ T cells (9–10). These NKRs have been shown to be functional. Certain NKRs are able to downmodulate cytotoxicity induced by TCR/CD3, and cross-linking of NKRs may inhibit cytolysis by CD8+ T cells (3). Additionally,

TCR-initiated stimulatory signals can be overridden by signals generated by inhibitory NKRs, preventing T cell cytokine release (11). In contrast, NKG2D is an activating receptor that is expressed on CD8+ T cells and some CD4+ T cells Selleck Tenofovir (12). NKG2D is a potent costimulator of TCR-mediated functions that up-regulates antigen-specific, T cell-mediated cytotoxicity directed against cells or tissues expressing stress-induced NKG2D ligands, particularly under conditions of suboptimal TCR engagement (13–14). In addition, NKG2D on T cells can function

independently of the TCR (14). Only a few studies have been published on the expression of NKRs on T cells in HIV infection. One research group found that HIV-specific CTL isolated from infected patients were inhibited in their cytolytic activity against HIV-expressing autologous target cells as a consequence of the surface expression of iNKR. Furthermore, addition of anti-NKR mAbs restored CTL cytolytic activity (15). This finding strongly suggests that iNKRs are involved in the downregulation of HIV-specific CTL activity. Consistent with this, coexpression of multiple iNKRs on CD8+ T cell clones derived from HIV-infected patients has been observed (16). Another study observed low expression of inhibitory NKRs on CD8+ T cells in HIV-infected, long-term non-progressors, indicating that a lack of iNKR-mediated functional inhibition may provide an additional mechanism of efficient control of viral spread in LTNPs (17). Moreover, the expression of NKG2D on NK cells was lower in HIV-infected patients (18).

Trichostrongylus retortaeformis: The establishment, development a

Trichostrongylus retortaeformis: The establishment, development and survival of nematodes in the small intestine caused significant villous atrophy, increased crypt hyperplasia, reduction in the height-depth villus-crypt ratio and local recruitment of plasma cells, eosinophils and lymphocytes, compared to the controls

(For all Fisher’s exact test: P < 0·05). No significant changes in the intensity of the damage were observed with the course of the infection. Graphidium strigosum: Consistent focal glandular destruction, epithelial dedifferentiation and higher recruitment of eosinophils, lymphocytes and plasma cells were observed in the stomach tissue of infected compared to control individuals

(For all Fisher’s exact test: P < 0·01). Overall, ABT-737 order both nematodes appeared to cause pathological damage by altering mucosa structure and recruitment of leucocytes to the site of infection. Trichostrongylus retortaeformis: The linear combination of IFN-γ, IL-4, IgA, IgG, eosinophils and lymphocytes, measured at the local site of infection (i.e. mucosa tissue or mucus of the SI-1 section), explained a large proportion of variation in the immune response to T. retortaeformis. The multivariate combination of these variables accounted for 64% of total variation in the first two principal components of a PCA (proportion of variance ± SD: PC-1 = 0·35 ± 1·44 and PC-2 = 0·29 ± 1·325). The first principal component was mainly driven by the effect of eosinophils (coeff. = 0·525), lymphocytes (0·562) and the opposite effect of IFN-γ all (−0·500). selleck chemical The second principal component was affected by mucus IgA (−0·570) and IgG (−0·567) and the opposite contribution of IL-4 (0·456). Ct values are inversely related to cytokine expression, so that, high values -or a positive correlation- represent low cytokine expression and vice-versa. Changes in T. retortaeformis abundance were examined in relation to the estimated principal components, and a significant positive relationship

was found with the second principal component (coeff. ± SE = 0·601 ± 0·274, d.f = 38, P < 0·05, Figure 7a), indicating that a decrease in parasite abundance was associated with an increase in IL-4 and antibody responses. No significant association was observed with the first principal component. Nematode abundance was tested against the variables selected in the PCA, and the results confirmed that T. retortaeformis infection was negatively associated with IL-4 (coeff. ± SE: 0·718 ± 0·348, P < 0·05) and positively associated with IFN-γ (−0·569 ± 0·247, P < 0·05). A negative relationship was also found with mucus IgG and mucosa eosinophils and lymphocytes (second-order interaction with time, for all P < 0·05, IgG: P = 0·056), while a positive association was observed with mucus IgA alone (P < 0·01).

8,11 In contrast, Maori and Pacific Islander peoples have a lower

8,11 In contrast, Maori and Pacific Islander peoples have a lower percentage body fat at any given BMI.12,13 Comparable percentage body fat was associated with a BMI 2–3 units greater in men and up to 4 units greater in women of the Pacific Islander population compared with Caucasians.13,14 There is no evidence that this is protective FDA approved Drug Library and the prevalence of diabetes and CVD are high in the Maori and Pacific Islander

population and associated with BMI. In data extracted from the 1997 National Nutrition survey, there were very significant increases in age-standardized attributable mortality for diabetes (10-fold increase), ischaemic heart disease (threefold increase) and stroke (twofold increase) in the higher than optimum BMI category (>21 kg/m2) for Maori as compared with non-Maori.15 A small study by McAuley et al.16 demonstrated that for any given BMI, Maori women are more insulin resistant than Caucasian controls. Therefore, there is no indication that using higher cut-offs to define obesity is justified in the Maori and Pacific

Islander population and standard criteria should apply.17 Databases searched: MeSH terms and text words for kidney transplantation were combined with MeSH terms and text words for living donor and combined with MeSH terms and text words for obesity and morbid obesity. The search was carried out in Medline O-methylated flavonoid (1950–July Week 3, 2008). The Cochrane Renal Group Trials Register HM781-36B was also searched for trials not indexed in Medline. Date of searches: 24 July 2008. Large epidemiological studies have demonstrated an association between obesity and mortality. In a subset of individuals aged 50 years who had never smoked, and were followed for 10 years, there was a two- to threefold increase in mortality for those with a BMI > 30 kg/m2.18 Obesity is strongly linked to Type 2 diabetes, hypertension, CVD, some cancers and arthritis, which each contribute to the increase in mortality. The mechanism for this relationship

may be related to insulin resistance and hyperinsulinaemia, with subsequent increases in impaired glucose tolerance, increased sympathetic activity, renal sodium retention and vascular tone. In spite of increased use of risk-modifying therapies such as lipid-lowering drugs and antihypertensives, there is no evidence of a reduction in the population risk associated with obesity over time.19 Cardiorespiratory fitness may modify this risk.20–22 A prospective observational study of 25 714 predominantly Caucasian men22 demonstrated that low fitness was common in obese men and an independent predictor of cardiovascular and all-cause mortality and increased the relative risk of mortality to a similar degree as does diabetes. A second important finding in this study was that for each risk factor studied (i.e.

The demographic data of study groups are presented in Table 1 Th

The demographic data of study groups are presented in Table 1. The study was approved by the Ethics Committee of the Medical University of Warsaw.

The venous blood samples were collected before breakfast, early morning. All the analysis Protein Tyrosine Kinase inhibitor were performed right after blood collection. First, anti-CD45-FITC and anti-CD14-PE was used for the lymphocyte gate setting at FSC/SSC graph. As a negative isotype controls the Ig2a-FITC and Ig2b-PE were applied. We analysed the proportion of following lymphocyte subtypes: T cells, B cells, T helper and T cytotoxic cells and the expression of CD25 and CTLA4 on CD4+ cells and CD25 on CD8+ cells with following mixtures of antibodies: CD3-FITC/CD19-PE (Becton-Dickinson Immunocytometry Systems, San Jose, CA, USA), CD4-FITC/CD8-PE, CD4-FITC/CD25-PE/CTLA4-Cy5, CD8-FITC/CD25-PE (Dako Cytomation, Glostrup, Denmark). The analyses were performed using three-colour flow cytometry method (FACS Calibur flow cytometer, Becton-Dickinson, San Jose, CA, USA). The cells were collected by Cellquest software. The analysis was performed in the same manner, with the same set of antibody and in the same conditions in patients and controls. The population of CD25high cells was gated manually and was well separated from

those with low CD25 expression (Fig. 1). The serum concentration of adiponectin selleck was measured using Human Adiponectin/Acrp30 Immunoassay kit (R&D System, Minneapolis, MN, USA) and ELISA method according to the prescription by the producer. Statistical analysis.  For data Cobimetinib cell line comparison the Mann–Whitney U-test was used, P < 0.05 regarded as significant. The relationships between the data were examined by the Spearman rank correlation coefficient. Correlations with both R ≥ 0.4 and P < 0.05 were considered relevant. To present the data we used proportion of cells. The absolute number of cells depends on the number of gated events

and on absolute number of lymphocytes. To present the proportion is more common in the literature and seems to be more objective in the comparative studies. In the analysis of the main lymphocyte subpopulations we found that the proportion of T cells was significantly higher in patients than in controls, so was the proportion of T cytotoxic cells (Table 2). The Th/Tc ratio was significantly lower in patients than in healthy subjects (1.12 versus 2.0, P = 0.03). The proportion of all CD4+/CD25+ cells and the population with high expression of CD25 on CD4+ cells defined as CD25high cell were shown in the Table 2, and on Fig. 2. The proportion of CD4+/CD25+ of all lymphocytes was significantly lower in COPD patients when compared with controls (median value was 15.3 versus 17.9%, respectively, P = 0.03). The proportion of CD25high cells in the COPD group was significantly lower than in controls, median value: 0.79% versus 1.54%, P = 0.027.

Few studies have looked at the effect of IL-2Ra induction on rena

Few studies have looked at the effect of IL-2Ra induction on renal transplant outcomes in recipients with differing immunological risk. The initial randomized placebo-controlled study of IL-2Ra induction by Nashan et al. included predominantly low- and intermediate-risk (mean of 3 HLA-mismatches and pre-transplant PRA of <5%) deceased-donor renal transplant recipients maintained on corticosteroids and cyclosporine. In this study, the use of IL-2Ra was associated with a significant reduction in biopsy-confirmed

acute rejection and steroid-resistant selleck rejection.10 Similarly, Lawen et al. undertook a randomized, double-blind, placebo-controlled study of IL-2Ra in low- to intermediate-risk renal transplant recipients receiving triple immunosuppressive medications comprising of corticosteroids, cyclosporine and mycophenolate mofetil.15 The majority of the recipients (>85%) were receiving primary grafts with a mean of 3 HLA-mismatches and PRA level of <3%. In contrast to the previous

study, there was only a non-significant trend in favour of using IL-2Ra induction over placebo in the incidence of acute rejection. Unlike the study by Nashan et al. the rejection risk in the study by Lawen et al. was lower (34–52% and 15–27%, respectively). Even though the immunological risk of study recipients was similar in both studies, the difference in rejection risk between studies may be explained by lower amount of maintenance immunosuppression (without antimetabolite)

in the study Endonuclease by Nashan et al. resulting in increased rejection risk. Other prospective studies of the addition of IL-2Ra Buparlisib induction to dual immunosuppressive regimen with steroids and cyclosporine or azathioprine-based triple immunotherapy in low- to intermediate-risk renal transplant recipients have reported a significant reduction of rejection risk compared with placebo.12,16 Despite the benefit in reducing rejection risk, IL-2Ra induction has not been shown to be associated with improved graft or patient outcomes in these studies, although registry data from the Collaborative Transplant Study of 112 122 deceased-donor transplant recipient showed improved graft survival with the use of IL-2Ra compared with no induction.17 In contrast, our study suggested that the use of IL-2Ra in low-risk recipients was not associated with reduced rejection risk or graft and patient outcomes. However, the low-risk recipients included in our study were of lower immunological risk compared with recipients in other studies, as only recipients fulfilling the stringent criteria of primary grafts with ≤2 HLA-mismatches and PRA < 10% were included for analysis. Although the benefit of IL-2Ra induction has been clearly shown to reduce rejection risk in low- to intermediate-risk renal transplant recipients, this benefit appears to be more apparent in renal transplant recipients maintained on cyclosporine-based dual or triple immunosuppressive regimen.

Taken together, we conclude that CTLA-4-Ig affects the level of c

Taken together, we conclude that CTLA-4-Ig affects the level of cytokines and chemokines in the affected tissue by significantly reducing IL-4, IL-1β, MIP-2 and IP-10. To analyse the effect of CTLA-4-Ig on systemic inflammation, serum samples taken 24 and 48 h after challenge were analysed by ELISA for the acute-phase proteins

SAP and haptoglobin. These factors have been shown to be reliable click here markers of inflammation in this model as their serum levels correspond to ear swelling (A.D.C. and C.H., data not shown). Furthermore, increased serum concentration of these components indicates systemic inflammation with involvement of the liver [18]. Figure 6b,d shows that serum levels of SAP and haptoglobin were reduced significantly following treatment with CTLA-4-Ig compared to control treatment at both 24 and 48 h after challenge in the DNFB-induced model, and in the oxazolone-induced Metformin solubility dmso model serum concentrations of haptoglobin were suppressed significantly after both 24 and 48 h (Fig. 6c). Similarly, SAP was reduced significantly after 48 h but not at 24 h (Fig. 6a). Based on these findings, we conclude that CTLA-4-Ig inhibits systemic inflammation as measured by circulating levels of SAP and haptoglobin. In the CHS model, it is not known whether CTLA-4-Ig exerts its effect in the sensitization

phase alone or whether the presence of CTLA-4-Ig is also important in the effector phase. To test this, we set up an adoptive Carnitine dehydrogenase transfer system in which donor mice were sensitized in the presence or absence of CTLA-4-Ig. After 5 days, cells from the draining lymph node were transferred to recipient mice which had been treated with CTLA-4-Ig 24 h earlier or left untreated. Recipient mice were subsequently challenged with DNFB and ear swelling was measured 24, 48 and 72 h after challenge. As shown in Fig. 7, mice transferred

with cells exposed to CTLA-4-Ig during both the sensitization phase and the challenge phase or during the sensitization phase alone (labelled +/+ and +/−, respectively) exhibited a significantly suppressed ear-swelling response compared to the untreated control group (labelled −/−). In contrast, the mice which were treated only with CTLA-4-Ig during the challenge phase (labelled −/+) exhibited ear swelling similar to the untreated mice. Taken together, these results indicate that CTLA-4-Ig exerts its immunosuppressive effect primarily during the sensitization phase. We next tested whether regulation of cytokines and chemokines in the inflamed tissue followed the same pattern as ear swelling by comparing levels of IL-1β, IL-4, IP-10 and MIP-2 in the adoptive transfer model treated with CTLA-4-Ig in the sensitization or challenge phase only.