Su.51. Scv-07 Peroral Formulation Protects Mice Against Experimental Tuberculosis Infection

Abstracts analyses, we have been able to identify highly immunogenic Class I and Class II peptides from CMV. Using synthetic antigen presenting cells, we plan to select and expand peptide-specific CD8+ and CD4+ T effector cells suitable for immunotherapy. doi:10.1016/j.clim.2006.04.476

Su.50. Distinct Regulatory T-Cells Induced By Repeated Injection of Toxic Shock Syndrome Toxin-1: A Comparative Study with Staphylococcal Enterotoxin a. Haowei Li, Anthony Chow. Department of Medicine, University of British Columbia, Vancouver, BC, Canada. Bacterial superantigens could activate a large number of CD4+ T-cells by cross-linking MHC Class II molecules and specific Vh segments of the T-cell receptor (TCR), triggering massive proliferation and cytokine production. Previous studies showed that repeated injection of superantigens, such as staphylococcal enterotoxin A (SEA) could induce CD4+ regulatory T-cells (Tregs), but not much is known about Tregs induced by toxic shock syndrome toxin-1 (TSST-1). We performed a side-by-side comparative study of Tregs induced by TSST-1 and SEA in C57B6 mice. Our data showed that TSST1-induced Tregs had higher expression of CD25 and CTLA-4 and produced higher levels of IL-10, IFN-g and TNF-a than SEA-induced Tregs. Interestingly, both TSST-1 and SEAinduced Tregs were proliferative in response to superantigen stimulation, however, TSST-1-induced Tregs proliferated more potently and even in the absence of superantigen stimulation. Moreover, in vitro co-culture experiments showed that TSST-1-induced Tregs could downregulate the cytokine responses triggered by either TSST-1 or SEA, while SEA-induced Tregs could only downregulate the cytokine response induced by SEA but not TSST-1. In vivo experiments further demonstrated that induction of Tregs with TSST-1 protected mice against lethal shock challenge by either TSST1 or SEA, while induction of Tregs with SEA could only protect mice against SEA. Analysis of the Vh segments of the TCRs showed that the broader suppressive function of TSST-1induced Tregs was not due to the presence of overlapping Vhreactive TCRs in these mice. In summary, our results showed that TSST-1-induced Tregs were more proliferative and had more potent and broader suppressive activities, which might be advantageous for their potential therapeutic applications in immunotherapy for various clinical conditions. doi:10.1016/j.clim.2006.04.477

Su.51. Scv-07 Peroral Formulation Protects Mice Against Experimental Tuberculosis Infection. Alexander Petrov,1 Natalia Pigareva,1 Alexander Kotov,1 Tatyana Vinogradova,2 Natalya Zabolotnyh,2 Cynthia Tuthill,3 Alexander Kolobov,1 Andrey Simbirtsev.1 1 Immunology, Verta, St. Petersburg, Russian Federation; 2 Experimental Immunology, Institute of Phtysiopulmonology, St. Petersburg, Russian Federation; 3 Pharmacology, SciClone Pharmaceuticals, Inc., San Mateo, CA

S177 SCV-07 is a novel peptide immunomodulatory drug. The goal of the present study was to compare the immunological activity of a peroral formulation and i.p. injections of SCV07 in intact healthy mice and in an experimental tuberculosis model. In accordance with our previous results we found elevated IL-2 activity in supernatants from ConAstimulated spleen cells in animals treated with 0.1 and 1.0 ug/kg SCV-07 i.p. Peroral administration of 0.1, 1.0 and 10.0 ug/kg of SCV-07 also led to elevated IL-2 production. We also detected substantial changes in thymocytes subpopulations, which were most intensive in groups treated with 1.0 ug/kg SCV-07 i.p. or per os. We found an approximately 10—25% decrease in the percentage of double-positive thymocytes accompanied with a 5—10% increase of double-negative and a 10—15% increase of CD4+ single-positive cells. To assess the protective activity of peroral formulation of SCV-07 in an experimental tuberculosis model, 4—6 week old C57BL/6 mice were inoculated i.v. with M.tuberculosis Erdman. Starting from day 12th after challenge, all mice were treated with isoniazid and rifampicin and divided into several groups that were additionally treated during 5 days with 0.1—1.0 ug/kg SCV-07 i.p. or 0.1—10.0 ug/kg SCV-07 per os. At day 45th after challenge there were significantly reduced macroscopic signs of pathology and significantly lower bacterial burden in lung tissue of animals treated with 1.0 ug/kg SCV-07 i.p. or per os compared to the control group. These findings were accompanied by a dramatic increase in BCG-specific proliferation and a decrease in BCG-induced IL-10 production by spleen cells in SCV-07 treated groups. Based on these findings, we suggest that the peroral formulation of SCV-07 retains its immunomodulatory properties and is as effective in protection against experimental tuberculosis in mice as parenterally administered drug. doi:10.1016/j.clim.2006.04.478

Su.52. CD4+CD25brightFOXP3+ Regulatory T-Cells Are Induced After Cardiac Surgery. Alvin Schadenberg,1 Bas Vastert,1 Jola Evens,3 Wietse Kuis,1 Hans van Vught,2 Koos Jansen,2 Berent Prakken.1 1Pediatric Immunology, Wilhelmina Children’s Hospital, UMCU, Utrecht, Netherlands; 2Pediatric Intensive Care, Wilhelmina Children’s Hospital, UMCU, Utrecht, Netherlands; 3 Pediatric Cardiothoracic Surgery, Wilhelmina Children’s Hospital, UMCU, Utrecht, Netherlands. Cardiac surgery induces a systemic inflammatory response. The balance between pro- and anti-inflammation is critical in determining clinical outcome. Little is known whether CD4CD25brightFOXP3+ regulatory T-cells play an active role in controlling acute inflammation following cardiac surgery. We investigated the kinetics of regulatory T-cells after cardiac surgery in children. Twenty children were investigated. Peripheral blood mononuclear cells were isolated before, immediately after, 24 and 48 hours after surgery and analysed by flowcytometry. In sorted CD4CD25 populations FOXP3 mRNA, was determined in 8 patients by semi-quantitative real-time PCR. Flowcytometric analysis shows a significant increase (+57%, p b 0.05) in