FIZZ1 potentiates the carbachol-induced tracheal smooth muscle contraction.

FIZZ1 is an adipokine highly expressed under inflammatory conditions, and yet, little is known of its function. In this study we examine the expression and function of FIZZ1 in an ovalbumin mouse model of asthma. Trachea from naïve or ovalbumin-sensitised and -challenged mice were compared for transcriptional, functional and proteomic differences using gene microarrays, ex vivo tracheal contraction, immunohistochemistry and Western blot analysis. FIZZ1 was expressed in ovalbumin-treated, but not naïve, trachea. Naïve trachea incubated with recombinant FIZZ1 exhibited denuded epithelium and contractile hyperresponsiveness. The FIZZ1-incubated trachea also exhibited an associated increased expression of phospho-c-Raf, phospho-extracellular signal-regulated kinase 1/2, phospho-p38, MLCK and MLC-20. These data demonstrate that FIZZ1 regulates tracheal smooth muscle contraction through impairment of the epithelium and activation of the mitogen-activated protein kinase pathway in muscle.

The anti-tumor effect of interleukin-12 is enhanced by mild (fever-range) thermal therapy.

The cytokine interleukin 12 (IL-12) has resulted in notable anti-tumor activity in animal models and in patients and as a result there is considerable interest in learning how to maximize its therapeutic potential while at the same time reducing its known toxic side effects. Strategies which could maintain its effectiveness while permitting reduced dosage could be especially valuable. In this study we used BALB/c mice bearing CT26 tumors as a model for testing whether combining murine IL-12 with a mild (fever range) whole body hyperthermia protocol could result in such a strategy. Our data revealed that 100 ng of IL-12/mouse/day used in combination with FR-WBH was as effective as one in which 300 ng of IL-12/mouse/day was used alone. Importantly, the mice receiving the combination treatment exhibited fewer treatment related toxicities compared to those that received high dose IL-12 alone. Initiation of the IL-12 treatment immediately after FR-WBH induced the greatest anti-tumor effect. This effect does not appear to depend on differences in IL-12-induced IFN-gamma, but may involve production of nitric oxide (NO), since treatment of mice with a NOS inhibitor, NG-monomethyl-L-arginine (L-NMA), abolishes the additive anti-tumor effect of the combination treatment. Collectively, these data suggest that modification of physiological parameters in the host by mild fever-like thermal stimuli may be an effective and feasible adjuvant for cytokine-based immunotherapeutic strategies.

Virulent Toxoplasma gondii strain RH promotes T-cell-independent overproduction of proinflammatory cytokines IL12 and gamma-interferon.

The aim of this study was the analysis of the cytokine response in BALB/c mice infected with the highly virulent RH or the weakly virulent Beverley strains of Toxoplasma gondii. Analysis of cytokine messages showed increased expression of IL12, IFN-gamma and TNF-alpha, but not IL4 mRNAs in spleen cells after infection with the T. gondii strains RH and Beverley. High levels of circulating IL12 and IFN-gamma were detected in the serum of mice infected with strain RH, although TNF-alpha levels remained low. In contrast, the same cytokines were detected at only low levels in the serum of mice infected with the Beverley strain. Administration of antibody against IL12 or IFN-gamma significantly delayed time to death of mice infected with strain RH compared to controls. T-Cell-deficient as well as normal mice were equally infected by strain RH, suggesting that T lymphocytes do not contribute to the response. Depletion of natural killer cells from the splenocyte population abolished the in vitro production of IFN-gamma. Together, our data suggest that the virulent strain RH induces in BALB/c mice a type 1 cytokine pattern with T-cell-independent overproduction of IL12 and IFN-gamma that may be involved in the pathogenesis of this micro-organism.

Efficacy and mechanisms of action of rmB7.2-Ig as an antitumor agent in combination with Adriamycin and Cytoxan chemotherapy.

The efficacy of chemotherapy for cancer is often limited by toxicity. Immune approaches to cancer immunotherapy, while promising for specificity and long-term protection, have not typically proven potent enough to generate significant therapeutic responses. We have shown therapeutic benefit using recombinant murine B7.2-Ig (rmB7.2-Ig) in murine tumor models. Efficacy was dependent on immune activity and was not associated with toxicity. Recently, the efficacy of rmB7.2-Ig was demonstrated in leukemia tumor models in combination with chemotherapeutic agents. To further explore the potential of this approach, we evaluated the efficacy in solid tumor models of rmB7.2-Ig given in combination with chemotherapeutics commonly used in clinical practice, testing the effects of dose and schedule. RmB7.2-Ig in combination with some chemotherapeutics enhances the activity and efficacy of reduced chemotherapeutic doses. However, the relative timing of chemotherapy and rmB7.2-Ig dosing can be important. Investigation of mechanisms of action based on histological studies suggests that inflammatory as well as T cell mechanisms comprise the response. Additional studies of mice deleted of B7.1, B7.2, and CTLA-4 suggest that the enhanced response induced by rmB7.2-Ig may not be mediated through CD28 ligation alone. The efficacy suggests potential for recombinant human B7.2-Ig as an adjuvant to chemotherapy in promoting immune-mediated mechanisms to augment the activity of chemotherapy.

Type I interferons and IL-12: convergence and cross-regulation among mediators of cellular immunity.

Therapeutic use of type I IFN (IFN-alpha/beta) has become common. Many of the diverse diseases targeted are marked by pathogenetic abnormalities in cell-mediated immunity (CMI), these cellular immune responses either causing injury to the host, lacking sufficient vigor for virus or tumor clearance, or both. In general, therapeutic efficacy is limited. It is thus notable that the pleiotropic effects of type I IFN on CMI remain poorly understood. We characterized the effects of type I IFN on the production of IL-12, the central immunoregulatory cytokine of the CD4(+) T cell arm of CMI. We show that type I IFN are potent inhibitors of IL-12 production by human monocytes/macrophages. The underlying mechanism involves transcriptional inhibition of the IL-12p40 gene, marked by down-regulation of PU.1 binding activity at the upstream Ets site of the IL-12p40 promoter. Type I IFN have previously been shown to be able to substitute for IL-12 in driving IFN-gamma production from T and NK cells. The ability of IFN-alpha/beta to suppress IL-12 production while up-regulating IFN-gamma production suggests a possible mechanistic basis for the difficulties of employing these cytokines in diseases involving abnormalities of CMI.

Dose-dependent and schedule-dependent effects of interleukin-12 on antigen-specific CD8 responses.

Interleukin-12 (IL-12) has been shown to play a central role in the innate and acquired immune responses. Its activities include enhancement of natural killer (NK) and cytotoxic T lymphocyte (CTL) activity and promotion of CD4 Th1 cell development. It has also been shown to provide potent activity as a vaccine adjuvant in generating antibody and T cell responses. We have investigated the efficacy of IL-12 protein in promoting CD8 T cell responses when it is used as an adjuvant for immunization. Studies using, as antigen, cDNA from an autologous antigen (P1A) as well as studies of responses to vaccinia virus-delivered self (gp100) and non-self (beta-galactosidase) antigens show that the dose and schedule of IL-12 administration can significantly affect adjuvant activity, leading to enhancement or suppression of antigen-specific responses.

IL-12-Dependent enhancement of CTL response to weak class I-restricted peptide immunogens requires coimmunization with T helper cell immunogens.

The effect of in vivo administration of rmIL-12 on the CTL response to immunization with a weakly immunogenic class I-restricted peptide emulsified in incomplete Freund's adjuvant was investigated. In the absence of IL-12, peptide-specific CTL responses were significantly greater following coimmunization with class I-restricted peptide and T helper cell antigens than following immunization with the class I-restricted peptide alone. IL-12-dependent enhancement of the CTL response to peptide immunization was demonstrated in the presence of, but not in the absence of, coimmunization with T helper cell antigen. These findings indicate that IL-12 enhancement of the CTL response to weak class I-restricted immunogens is T helper cell dependent. Treatment with rmIL-12 also enhanced the CTL response to immunization with cDNA encoding both CTL and T helper cell epitopes. These findings are relevant to the design of vaccines containing tumor-associated class I-restricted peptides currently being tested as an immunotherapy for cancer patients.

A CTL assay requiring only 150 microliter of mouse blood.

In this paper, we present a method for measuring antigen specific cytotoxic T lymphocyte (CTL) activity from individual mouse peripheral blood samples without animal sacrifice. Peripheral blood cells are stimulated in vitro with a cocktail of antigen, cytokines, costimulatory molecules and irradiated feeder cells resulting, 7 days later, in a readily detectable antigen specific signal from a well plated under limiting dilution conditions. This highly sensitive and antigen specific assay is more efficient than conventional CTL assays and thus increases the number of mice that can be tested in a single assay. Since blood samples can be assayed from an individual mouse at multiple times during the course of an in vivo study, the assay can facilitate and strengthen correlative studies on CTL responses and in vivo results.