Addition or removal of concomitant methotrexate alters adalimumab effectiveness in rheumatoid arthritis but not psoriatic arthritis.

Objective: Randomized trials have shown that concomitant methotrexate (MTX) augments the effectiveness of tumour necrosis factor (TNF) inhibitors in rheumatoid arthritis (RA), but its benefit in psoriatic arthritis (PsA) has not been demonstrated. The goal of this study was to examine whether the impact of concomitant MTX on therapeutic outcomes in patients with PsA was similar to its effects in RA. Methods: We used data from highly comparable and concurrent observational studies of patients with PsA (N = 1424) or RA (N = 3148) who initiated adalimumab therapy during routine clinical care. The 28-joint Disease Activity Score (DAS28) and patient-reported pain scores were evaluated in patients who received 24 months of continuous treatment with adalimumab monotherapy or adalimumab + MTX and in patients who initiated or stopped concomitant MTX during ongoing adalimumab therapy. Results: Twenty-four months of continuous treatment with adalimumab + MTX was superior to adalimumab monotherapy in RA patients, while no significant difference was observed in patients with PsA. RA patients who added MTX during the study showed significant individual improvements in DAS28 and pain scores at 6 months after the change in therapy, while those who removed MTX had slight increases in disease activity. In contrast, in patients with PsA, neither initiation nor removal of MTX during continuous adalimumab therapy had a significant effect on therapeutic outcomes. Conclusion: Addition of MTX to adalimumab confers further therapeutic benefit in patients with RA, but not in those with PsA, suggesting differences in MTX effects in these two patient populations. Clinicaltrials.gov NCT01078090, NCT01077258, NCT01111240.

Immunotherapeutic maintenance treatment with toll-like receptor 9 agonist lefitolimod in patients with extensive-stage small-cell lung cancer: results from the exploratory, controlled, randomized, international phase II IMPULSE study.

Background: The immune surveillance reactivator lefitolimod (MGN1703), a DNA-based TLR9 agonist, might foster innate and adaptive immune response and thus improve immune-mediated control of residual cancer disease. The IMPULSE phase II study evaluated the efficacy and safety of lefitolimod as maintenance treatment in extensive-stage small-cell lung cancer (ES-SCLC) after objective response to first-line chemotherapy, an indication with a high unmet medical need and stagnant treatment improvement in the last decades. Patients and methods: 103 patients with ES-SCLC and objective tumor response (as per RECIST 1.1) following four cycles of platinum-based first-line induction therapy were randomized to receive either lefitolimod maintenance therapy or local standard of care at a ratio of 3 : 2 until progression or unacceptable toxicity. Results: From 103 patients enrolled, 62 were randomized to lefitolimod, 41 to the control arm. Patient demographics and response patterns to first-line therapy were balanced. Lefitolimod exhibited a favorable safety profile and pharmacodynamic assessment confirmed the mode-of-action showing a clear activation of monocytes and production of interferon-gamma-induced protein 10 (IP-10). While in the intent-to-treat (ITT) population no relevant effect of lefitolimod on progression-free and overall survival (OS) could be observed, two predefined patient subgroups indicated promising results, favoring lefitolimod with respect to OS: in patients with a low frequency of activated CD86+ B cells (hazard ratio, HR 0.53, 95% CI: 0.26-1.08; n = 38 of 88 analyzed) and in patients with reported chronic obstructive pulmonary disease (COPD) (HR 0.48, 95% CI: 0.20-1.17, n = 25 of 103). Conclusions: The IMPULSE study showed no relevant effect of lefitolimod on the main efficacy end point OS in the ITT, but (1) the expected pharmacodynamic response to lefitolimod, (2) positive OS efficacy signals in two predefined subgroups and (3) a favorable safety profile. These data support further exploration of lefitolimod in SCLC.

Absence of specific alternatively spliced exon of CD44 in macrophages prevents colitis.

CD44 is a transmembrane molecule appearing in numerous isoforms generated by insertions of alternatively spliced variant exons (CD44v) and having various binding partners. CD44v7 on T cells was proposed to promote colitis by preventing T-cell apoptosis. Here we demonstrate that Cd44v7-deficient T cells - like Cd44 wild-type (Cd44WT) T cells - provoked disease in two different colitis models: the model induced by CD4+CD45RBhigh T-cell transfer into Rag2-deficient mice and a new model based on ovalbumin (OVA)-specific T-cell transfer into Rag-sufficient, OVA-challenged mice. In contrast, CD44v7 absence on macrophages in recipient mice prevented colitis. Prevention was associated with the downregulation of signal transducer and activator of transcription 3 (STAT3)-activating and Foxp3-counteracting interleukin-6 (IL-6), lower numbers of phospho-STAT3-containing lymphocytes, and higher Foxp3+ T-cell counts in the colon. Consequently, the protected colons showed lower IL-12, IL-1ß expression, and decreased interferon-γ levels. Importantly, stimulation of T cells by Cd44v7-deficient macrophages induced upregulation of Foxp3 in vitro, while cotransfer of Cd44WT macrophages into Cd44v7-deficient mice reduced Foxp3+ T-cell counts and caused colitis. Accordingly, the CD44v7 ligand osteopontin, whose levels were elevated in Crohn's disease, specifically induced IL-6 in human monocytes, a cytokine also increased in these patients. We suggest macrophage-specific targeting of the CD44v7 pathway as a novel therapeutic option for Crohn's disease.

The TLR9 agonist MGN1703 triggers a potent type I interferon response in the sigmoid colon.

Toll-like receptor 9 (TLR9) agonists are being developed for treatment of colorectal and other cancers, yet the impact of these drugs on human intestines remains unknown. This, together with the fact that there are additional potential indications for TLR9 agonist therapy (e.g., autoimmune and infectious diseases), led us to investigate the impact of MGN1703 (Lefitolimod) on intestinal homeostasis and viral persistence in HIV-positive individuals. Colonic sigmoid biopsies were collected (baseline and week four) from 11 HIV+ individuals on suppressive antiretroviral therapy, who received MGN1703 (60 mg s.c.) twice weekly for 4 weeks in a single-arm, phase 1b/2a study. Within sigmoid mucosa, global transcriptomic analyses revealed 248 modulated genes (false discovery rate<0.05) including many type I interferon (IFN)-stimulated genes. MGN1703 increased the frequencies of cells exhibiting MX1 (P=0.001) and ISG15 (P=0.014) protein expression. No changes were observed in neutrophil infiltration (myeloperoxidase; P=0.97). No systematic effect on fecal microbiota structure was observed (analysis of similarity Global R=-0.105; P=0.929). TLR9 expression at baseline was inversely proportional to the change in integrated HIV DNA during MGN1703 treatment (P=0.020). In conclusion, MGN1703 induced a potent type I IFN response, without a concomitant general inflammatory response, in the intestines.

Immune response of healthy horses to DNA constructs formulated with a cationic lipid transfection reagent.

BACKGROUND: Deoxyribonucleic acid (DNA) vaccines are used for experimental immunotherapy of equine melanoma. The injection of complexed linear DNA encoding interleukin (IL)-12/IL-18 induced partial tumour remission in a clinical study including 27 grey horses. To date, the detailed mechanism of the anti-tumour effect of this treatment is unknown. RESULTS: In the present study, the clinical and cellular responses of 24 healthy horses were monitored over 72 h after simultaneous intradermal and intramuscular application of equine IL-12/IL-18 DNA (complexed with a transfection reagent) or comparative substances (transfection reagent only, nonsense DNA, nonsense DNA depleted of CG). Although the strongest effect was observed in horses treated with expressing DNA, horses in all groups treated with DNA showed systemic responses. In these horses treated with DNA, rectal temperatures were elevated after treatment and serum amyloid A increased. Total leukocyte and neutrophil counts increased, while lymphocyte numbers decreased. The secretion of tumour necrosis factor alpha (TNFα) and interferon gamma (IFNγ) from peripheral mononuclear blood cells ex vivo increased after treatments with DNA, while IL-10 secretion decreased. Horses treated with DNA had significantly higher myeloid cell numbers and chemokine (C-X-C motif) ligand (CXCL)-10 expression in skin samples at the intradermal injection sites compared to horses treated with transfection reagent only, suggesting an inflammatory response to DNA treatment. In horses treated with expressing DNA, however, local CXCL-10 expression was highest and immunohistochemistry revealed more intradermal IL-12-positive cells when compared to the other treatment groups. In contrast to non-grey horses, grey horses showed fewer effects of DNA treatments on blood lymphocyte counts, TNFα secretion and myeloid cell infiltration in the dermis. CONCLUSION: Treatment with complexed linear DNA constructs induced an inflammatory response independent of the coding sequence and of CG motif content. Expressing IL-12/IL-18 DNA locally induces expression of the downstream mediator CXCL-10. The grey horses included appeared to display an attenuated immune response to DNA treatment, although grey horses bearing melanoma responded to this treatment with moderate tumour remission in a preceding study. Whether the different immunological reactivity compared to other horses may contributes to the melanoma susceptibility of grey horses remains to be elucidated.

Influences of age and sex on leukocytes of healthy horses and their ex vivo cytokine release.

Leukocytes and their functional capacities are used extensively as biomarkers in immunological research. Commonly employed indicators concerning leukocytes are as follows: number, composition in blood, response to discrete stimuli, cytokine release, and morphometric characteristics. In order to employ leukocytes as biomarkers for disease and therapeutic monitoring, physiological variations and influencing factors on the parameters measured have to be considered. The aim of this report was to describe the ranges of selected leukocyte parameters in a sample of healthy horses and to analyse whether age, sex, breed, and sampling time point (time of day) influence peripheral blood leukocyte composition, cell morphology and release of cytokines ex vivo. Flow cytometric comparative characterisation of cell size and complexity in 24 healthy horses revealed significant variance. Similarly, basal release of selected cytokines by blood mononuclear cells also showed high variability [TNFα (65-16,624pg/ml), IFNγ (4-80U/ml), IL-4 (0-5069pg/ml), IL-10 (49-1862pg/ml), and IL-17 (4-1244U/ml)]. Each animal's age influenced leukocyte composition, cell morphology and cytokine release (TNFα, IL-4, IL-10) ex vivo. Geldings showed smaller monocytes and higher spontaneous production of IL-10 when compared to the mares included. The stimulation to spontaneous release ratios of TNFα, IL-4 and IL-17 differed in Warmblood and Thoroughbred types. Sampling time influenced leukocyte composition and cell morphology. In summary, many animal factors - age being the dominant one - should be considered for studies involving the analysis of equine leukocytes. In addition, high inter-individual variances argue for individual baseline measurements.

[Chronic inflammatory intestinal diseases. Pathophysiology and therapy]. / Chronisch entzündliche Darmerkrankungen. Pathophysiologie und Therapie.

The pathogenesis and therapy of chronic inflammatory intestinal diseases are characterized by an obvious discrepancy. There is extensive agreement that the pathogenesis is substantially based on a disruption of the barrier of the intestinal mucous membrane against luminal bacteria. This has been demonstrated in recent years by evidence from various disciplines, in particular from genetics, microbiology, morphology and innate immunology. However, there is also the evidence-based therapy which, as in the past, is aimed against the effectors of the adaptive immune system. In this case the therapy with biologicals is more aggressive and takes the risk of a series of undesired side-effects. This dichotomy of pathological knowledge and therapeutic innovation is not only medically unsatisfactory but also makes it difficult to present a consistent picture of these symptoms. Despite this an attempt will be made to bridge these inconsistencies and to demonstrate possible future developments which will lead to a final causal therapy. An extended version of this article appears in our newly published book "Colitis ulcerosa und Morbus Crohn".

CD44v7 ligation downregulates the inflammatory immune response in Crohn's disease patients by apoptosis induction in mononuclear cells from the lamina propria.

Deletion of exon CD44v7 abrogates experimental colitis by apoptosis induction in intestinal mononuclear cells. Here we show that CD44v7 expression was upregulated upon CD40 ligation in human mononuclear cells, and examined whether ligation of CD44v7 also affects activation and apoptosis in lamina propria mononuclear cells (LPMC) from Crohn's disease (CD) patients. Thirty five patients with chronic inflammatory bowel disease (IBD), fourteen controls and four patients with diverticulitis were evaluated. CD44v7 was upregulated predominantly in the inflamed mucosa of CD patients. Furthermore, incubation with an anti-CD44v7 antibody induced apoptosis in LPMC isolated from inflamed mucosa of CD patients, but not from non-inflamed mucosa, from patients with ulcerative colitis (UC) or from normal controls. CD40 ligation and simultaneous incubation with anti-CD44v7 significantly downregulated CD80 in dendritic cells, thus inhibiting a critical second signal for naive T-cell activation. The apoptotic signal was mediated via the intrinsic mitochondrial pathway with decreased Bcl-2 and increased 7A6 (a mitochondrial membrane protein) expression. It was Fas independent and required caspases-3 and -9 activation. The process is highly specific for macrophage activation via CD40. These findings point to a novel mechanism of apoptosis induction in CD patients mediated by CD44v7 ligation.

Cyclophosphamide pulse therapy followed by azathioprine or methotrexate induces long-term remission in patients with steroid-refractory Crohn's disease.

BACKGROUND: In patients with steroid-refractory Crohn's disease, the therapeutic goal is to achieve both rapid remission and maintenance of clinical response. AIM: To evaluate the long-term benefit in patients treated with cyclophosphamide pulse therapy and azathioprine or methotrexate, a combination shown to be effective in a recent pilot study. METHODS: Sixteen patients with acute steroid-refractory Crohn's disease participated in a prospective open-labelled uncontrolled pilot study between December 1998 and June 2003. All had a median number of 4 monthly pulses of intravenous cyclophosphamide (750 mg) and were followed until relapse of the disease. RESULTS: Thirteen of 16 patients (81%) achieved remission within 8 weeks after two pulses of cyclophosphamide in combination with azathioprine or methotrexate, with a Crohn's Disease Activity Index decrease from 294 to 111 (median). Remission sustained for 19 months (median, range: 1-45). Moreover, eight patients with pyoderma gangrenosum and erythema nodosum who responded to cyclophosphamide have maintained their remission for up to 30 months. CONCLUSIONS: In steroid refractory patients with Crohn's disease, cyclophosphamide is highly effective to induce remission. This uncontrolled study indicates that cyclophosphamide-induced remission is long-lasting under standard immunosuppressive therapy.

Critical comment: analyzing the effect of novel therapies on cytokine expression in inflammatory bowel disease: do cytokine levels reflect clinical response?

Over the past several years, research in the field of cytokine production and function has become indispensable to understand the immunopathology of chronic intestinal inflammation. Thereupon, clinical studies analyzing cytokine production have generated a tremendous amount of data. In patients with inflammatory bowel disease, several studies examined pro-inflammatory cytokines in gut tissue and plasma, but a clear interpretation of the results with respect to disease activity or therapeutic response has been hampered by patient- and sample-related pitfalls.

Cytokine and Ig-production by CG-containing sequences with phosphorodiester backbone and dumbbell-shape.

BACKGROUND: Immunostimulatory oligodeoxynucleotides (CpG-ODN) usually contain phosphorothioate (PS) backbones for nucleotide protection, which may result in some nonspecific side-effects like prolongation of coagulation time. OBJECTIVE: The aim of the present study was to investigate the immunomodulatory potential of DNA molecules without PS backbones. Thus, we designed phosphorodiester (PO) molecules with a dumbbell-like covalently-closed structure (dSLIM-30L1). METHODS: We analyzed their effects on peripheral blood mononuclear cells (PBMC) from spontaneous high and low immunoglobulin (Ig)E producer (allergic and nonallergic donors) in comparison with linear CpG-ODN (lin-30L1) with PS backbones, using enzyme-linked immunosorbent assay and flow cytometry. RESULTS: We observed a decrease of spontaneous IgE levels in PBMC from high IgE producer of approximately 27% with both dSLIM-30L1 and lin-30L1. In addition, both molecules enhanced the production of IgA, IgM and IgG1/IgG2, but with a slightly different pattern. Both molecules stimulated the secretion of the T(H)1-like cytokines interleukin (IL)-2, interferon-gamma and IL-12p40 and the pro-inflammatory cytokine IL-6. The immunomodulatory potential of dSLIM-30L1 and lin-30L1 was also effective in PBMC from nonallergic donors, as was confirmed for IL-2, IL-12p40, IgG1/IgG2 and IgM. CONCLUSION: Our data show an inhibition of IgE production but also enhancement of the inflammatory cytokine response in PBMC from allergic and nonallergic donors by covalently-closed PO-based dSLIM-30L1 with a pattern similar to that of linear PS-based lin-30L1, while avoiding PS-modifications and thus PS-mediated side-effects. Whether such molecules are useful for the treatment of allergic diseases will need further clarification by appropriate in vivo studies.

Short-term treatment with anti-CD44v7 antibody, but not CD44v4, restores the gut mucosa in established chronic dextran sulphate sodium (DSS)-induced colitis in mice.

Increased expression of CD44 variant isoforms have been shown on the inflammatory infiltrates in human and mouse colitis and blockade or deletion of CD44 isoforms inhibit experimental colitis. The objective of this study was to find out if short-term treatment of CD44 antibodies specific to CD44v7, but not to other variant isoforms, suppresses leucocyte-endothelial interaction in chronic dextran sodium sulphate (DSS)-induced colitis in mice. Chronic colitis was induced by oral administration of four cycles of 5% DSS in BALB/c mice. Expression of CD44 was investigated on isolated mononuclear cells of the gut immune system. In established colitis, mice were treated with antibodies against CD44v7 or CD44v4 three times in 7 days. Intravital microscopy was used to study leucocyte-endothelial interactions and leucocyte extravasation. As a marker of inflammatory infiltrates myeloperoxidase was quantified in gut tissue. CD44-induced apoptosis was determined by fluorescence staining of hypodiploidic cell nuclei. In chronic DSS-induced colitis both CD44 variant isoforms, v4 and v7 were significantly up-regulated on mononuclear cells. However, whereas anti-CD44v7 antibody treatment induced a marked restoration of the gut mucosa and significantly reduced endothelial sticking and extravasation of circulating leucocyte in vivo (P < 0.01), application of anti-CD44v4 or an isotype control antibody had no anti-inflammatory effect. A significant reduction of myeloperoxidase activity was detected after blockade of CD44v7, but not v4. Short-term treatment with anti-CD44v7 antibody blocks T cell extravasation and recruitment to the intestinal mucosa and cures established experimental colitis.

DNA immunisation with minimalistic expression constructs.

The low efficacy obtained in large animals makes plasmid-based DNA vaccines commercially unviable. Another concern is the presence of antibiotic resistance markers on virtually all conventional plasmids. Here we describe the use of minimalistic, immunogenically defined gene expression (MIDGE) vectors for DNA vaccination. MIDGE are linear, covalently-closed vectors containing all the essential information for gene expression and none of the non-essential and potentially dangerous plasmid backbone sequences. MIDGE vectors can also be chemically modified on both ends at defined positions allowing targeting of the DNA to specific cell types or cellular compartments. Immunisation of mice with simple and end-modified MIDGE vectors showed that they are efficacious tools to generate and/or manipulate antigen-specific immune responses.

An interleukin 12 p40-IgG2b fusion protein abrogates T cell mediated inflammation: anti-inflammatory activity in Crohn's disease and experimental colitis in vivo.

BACKGROUND AND AIMS: Interleukin-12 (IL-12), a p35/p40 heterodimer, plays a pivotal role in the immune response in Crohn's disease (CD). Since IL-12 p40 dimers act as IL-12 antagonists, we assayed p40 dimer proteins to modulate chronic intestinal inflammation. METHODS: We generated a fusion protein consisting of the IL-12(p40) subunit fused to the constant region of IgG2b. IL-12(p40)-IgG2b was tested in a murine 2,4,6,-trinitrobenzene sulphonic acid (TNBS) colitis model and in lamina propria mononuclear cells (LPMNC) from patients with CD in vitro. RESULTS: Dimeric IL-12(p40)-IgG2b fusion protein bound specifically to the IL-12 receptor. In concentrations <10(-7) M, it acted as an IL-12 antagonist as it inhibited interferon gamma (IFN-gamma) secretion, suppressed proliferation, and increased apoptosis of LPMNC from patients with CD. However, in concentrations >10(-6) M, IL-12(p40)-IgG2b increased IFN-gamma secretion and lymphocyte proliferation thereby acting as an IL-12 agonist. In TNBS colitic mice, IL-12(p40)-IgG2b decreased mortality (10% v 68%), prevented body weight loss, reduced tumour necrosis factor alpha, and increased IL-10 secretion. CONCLUSIONS: The IL-12(p40)-IgG2b fusion protein has dichotomic properties as a specific IL-12 antagonist and selective repressor of mucosal inflammation at low concentration and as an IL-12 agonist at high concentration.

Downregulation of CD44v6 in colorectal carcinomas is associated with hypermethylation of the CD44 promoter region.

Overexpression of the cell adhesion protein CD44v6 has been demonstrated in colorectal cancer and other gastrointestinal tumors. While CD44v6 is upregulated in benign colorectal adenomas and well-differentiated colorectal cancer tissues, downregulation frequently occurs during disease progression. The mechanism of downregulation, however, is unknown. Therefore, we evaluated the methylation status of the CD44 promoter as a mechanism for decreased CD44v6 expression in advanced colorectal carcinomas. We demonstrated by methylation-sensitive restriction enzyme digestion that the CpG islands of the CD44 promoter were methylated in 6/21 (28%) of benign colorectal adenomas. Interestingly, in colorectal carcinomas the frequency of promoter methylation was significantly increased (10/19; 53%) compared to 7/21 (33%) in the corresponding normal mucosa. Methylation seems to be associated with a more advanced cancer stage, but the trend did not reach statistical significance. In colorectal carcinomas with CD44 promoter methylation CD44v6 mRNA was detected by reverse transcription-polymerase chain reaction in 3/10 carcinomas, whereas in tumors without CD44 promoter methylation CD44v6 expression was observed in 8/9 (P

The gut as an organ of immunology.

BACKGROUND: In normal conditions human gut mucosa is infiltrated with a large number of mononuclear cells due to continuous stimulation by luminal antigens. This state of "physiological" inflammation is tightly controlled, as several mucosal cells interact to maintain an appropriate local immune response. Moreover, gut-associated lymphoid tissue must constantly distinguish harmless antigens that are present in food and on commensal bacteria from pathogenic microbes. INTERVENTIONS AND RESEARCH: The oral administration of soluble protein antigens induces a state of systemic immunological unresponsiveness specific to the fed protein, termed oral tolerance. The two major mechanisms to explain oral tolerance are anergy/deletion of autoreactive lymphocytes and active suppression. Changes in the pathways of immune activation are detected in chronic intestinal inflammation, such as inflammatory bowel disease or celiac disease. CONCLUSION: An appreciation of the current knowledge of the gut immune system is of importance for understanding and development of new treatment modalities in chronic intestinal inflammation.

Safety and efficacy of intravenous pulse cyclophosphamide in acute steroid refractory inflammatory bowel disease.

BACKGROUND AND AIMS: One major problem in the management of steroid refractory attacks of patients with inflammatory bowel disease (IBD) is the establishment of a rapidly acting immunosuppressive regimen. Based on its well known efficacy in systemic vasculitis, intravenous cyclophosphamide pulse therapy was used in refractory IBD patients to evaluate both its efficacy and safety. METHODS: Between December 1998 and May 2001, seven patients (Crohn's disease, n=5; indeterminate colitis, n=1) with severe steroid refractory IBD (Crohn's disease activity index (CDAI) 264-479 points) received 4-6 cycles of monthly treatment with intravenous cyclophosphamide (750 mg) in a prospective uncontrolled pilot study. RESULTS: All patients improved after two intravenous pulses of cyclophosphamide and six of seven patients achieved complete remission (CDAI <150 points). One patient with Crohn's disease of the small and large bowel showed an impressive clinical response but did not enter into remission. Tapering to low dose steroids was possible in all responders. Remission was maintained in all patients for 18 months (median) but required a second course of intravenous pulse cyclophosphamide in one patient. The drug was well tolerated except for two episodes of candida oesophagitis. CONCLUSIONS: Intravenous pulse cyclophosphamide may be a safe and effective treatment in patients with severe IBD unresponsive to steroid treatment and merits evaluation in a controlled trial.

DNA vaccination with linear minimalistic (MIDGE) vectors confers protection against Leishmania major infection in mice.

Immunization protocols based on priming with plasmid DNA and boosting with recombinants of vaccinia virus (rVV) encoding the same antigen offer great promise for the prevention and treatment of many parasitic and viral infections for which conventional vaccination has little or no effect. To overcome some of the potential problems associated to the use of plasmids, we have developed minimalistic, immunogenically defined, gene expression (MIDGE((R))) vectors. These linear vectors contain only the minimum sequence required for gene expression and can be chemically modified to increase the immune response. Here, we demonstrate that MIDGE vectors coding for the LACK antigen confer a highly effective protection against Leishmania infection in susceptible Balb/c mice. Protection is achieved at lower doses of vector compared to conventional plasmids. This efficacy could be greatly improved by the addition of a nuclear localization signal (NLS) peptide to the end of the MIDGE vector. In fact, immunization with two doses of NLS-modified MIDGE conferred similar or even better protection than that achieved by priming with plasmid DNA followed by boosting with rVV. These results demonstrate that MIDGE vectors are a good alternative to plasmid and rVV for immunization.

Increased expression of interleukin-12 receptor beta(2) on lamina propria mononuclear cells of patients with active Crohn's disease.

BACKGROUND AND AIMS: Since interleukin-12 is pathogenetically involved in Crohn's disease (CD) but not in ulcerative colitis (UC), expression and mechanisms of induction of interleukin-12 receptor (IL-12R) subunits beta(1) and beta(2) were analyzed in lamina propria mononuclear cells (LPMNC) of patients with CD and UC. PATIENTS AND METHODS: LPMNC from patients with CD ( n=17), UC ( n=14), and controls ( n=19) were isolated by standard techniques. IL-12R beta(1) and IL-12R beta(2) transcripts were semiquantified by RT-PCR, and expression of IL-12R beta(2) chain was characterized by flow cytometry. LPMNC were activated by cross-linking with anti-CD3 antibodies and B7-1 costimulation. RESULTS: IL-12R beta(1) and IL-12R beta(2) transcript concentrations were higher in inflamed specimens than in noninflamed segments of patients with CD but not in UC. Increased percentage of mucosal CD4(+)/IL-12R beta(2)(+) cells was observed in active CD, but not UC. In vitro stimulation of LPMNC with anti-CD3 antibodies resulted in an increase in IL-12R beta(1) transcripts irrespective of B7-1 mediated costimulation (84% and 95%, respectively). However, increased expression of IL-12R beta(2) mRNA (110%) was detected only after B7-1 costimulation. CONCLUSION: Our data indicate that increased mucosal expression of IL-12R beta(2) on LPMNC in CD but not in UC may be the result of B7-1 costimulation. Modulation or inhibition of IL-12R beta(2) expression on LPMNC could provide a selective therapeutic approach in CD.