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e22129 Background: Ovarian cancer is diagnosed in more than 190,000 new patients every year and is known to have the highest mortality rate among gynaecologic cancers. The type of immune cells that are present within the tumor microenvironment can play a crucial role in the survival of patients. However, little is known about the dynamics of the tumor-infiltrating immune cells during disease progression. Methods: We studied the immune cells infiltrating the tumor tissue of ovarian cancer patients at different stages of disease. We analysed the patterns of T lymphocytes in fresh tumor tissue as well as blood samples of 44 newly diagnosed ovarian cancer patients by flow cytometry. To evaluate whether regulatory T cells (Tregs) develop in situ or migrate to tumor tissue, we measured a concentration of chemokine CCL22 in tumor cell culture supernatants. We also determined the expression of CCR4 on circulating as well as tumor-infiltrating Tregs by flow cytometry. Results: The early stages of development of ovarian carcinomas were characterized by a strong Th17 immune response, whereas in stage II patients, recruitment of high numbers of Th1 cells was observed. In disseminated tumors (stage III-IV), we detected a dominant population of Helios+ activated regulatory T cells along with high numbers of macrophages and immature myeloid dendritic cells. Tumor-infiltrating Tregs had markedly lower expression of CCR4 than circulating Tregs, and the numbers of tumor-infiltrating Tregs significantly correlated with the levels of CCL22 in ovarian tumor cell culture supernatants, suggesting their recruitment via a CCR4/CCL22 interaction. CCL22 was mainly produced by tumor cells, macrophages and mDCs in the primary ovarian tumors, and its expression markedly increased in response to IFNgamma. Conclusions: Taken together, the specific recruitment of Tregs, probably triggered by inflammatory stimuli, leads to a significant immune suppression in the advanced stages of ovarian cancer.

8501 Background: Despite frequent induction of tumor antigen-specific T cells in melanoma patients following vaccination, tumor regressions remain rare. This observation prompted systematic analysis of the melanoma tumor microenvironment to identify factors that may influence the effector phase of the anti-tumor immune response. Methods: Gene expression profiling using the Affymetrix platform was performed on a series of melanoma metastases, melanoma cell lines, and primary melanocyte cell lines. Confirmatory assays were done by real-time RT-PCR, protein array, immunohistochemistry (IHC), and in vitro chemokine migration assays. Results: Non- supervised hierarchical clustering revealed 3 major subsets of tumors, with the main clustering based on differential expression of T cell-derived transcripts. The presence of CD8+ T cells was confirmed by IHC. Tumors that contained T cells uniquely expressed high levels of multiple chemokines. Protein array confirmed high expression of CCL2, CCL4, and CCL5; real-time RT-PCR additionally confirmed relatively high levels of CXCL9, CXCL10, and CCL3 transcripts. Transwell assays confirmed that each of these 6 chemokines recruited CD8+ effector cells in vitro. Conclusions: We have identified a set of 6 chemokines that likely regulates recruitment of activated T cells into melanoma metastases. Tumors that lack such chemokines might not be capable of supporting the effector phase of the anti-tumor immune response. We suggest that chemokine profiling of tumor sites should be performed in clinical trials of active immunotherapy. No significant financial relationships to disclose.

The mechanisms underlying immune tolerance during pregnancy are poorly understood. We recently proposed a crucial role of T regulatory cells (Treg) in avoiding immunological rejection of the fetus, since we observed diminished number and function of Treg in abortion-prone mice. We further confirmed the protective role of Treg during pregnancy by transferring pregnancy-induced Treg into abortion-prone mice, which prevented rejection. Here, we analyzed the mechanisms involved in Treg-mediated protection. We transferred mice undergoing abortion with Treg from mice having normal pregnancies, including normal pregnant and abortion-prone mice as controls. We evaluated decidual lymphocytes for their cytokine profile. The mRNA levels for several tolerance-associated cytokines were also analyzed. As expected, Treg therapy prevented abortion, while expanding the peripheral and thymic Treg population. Locally, augmented foxp3 levels could be observed. Surprisingly, after therapy the decidual levels of the Th1 cytokines IFN-γ and TNF-α were not diminished. The transfer of Treg dramatically up-regulated the expression of LIF, TGF-β and HO-1 at the fetal-maternal interface. Our data suggest that Treg-treatment can not prevent T cell infiltration or high Th1 levels but is able to create a privileged tolerant microenvironment at the fetal-maternal interface, further shedding light onto the molecular mechanisms involved in pregnancy tolerance.

In cases of adult T cell leukaemia neoplastic T cell infiltration in the skin was accompanied by an increase in Langerhans cells. This is in keeping with the view that Langerhans cells may induce antigen-specific and allogenic T cell activation.

The immunologic response in small-intestine transplantation is characterized by an interaction between rejection and graft-versus-host reaction (GvHR) (Deltz 1981). In a fully allogeneic donor-recipient combination, an interaction of both reactions occurs (Deltz 1984). As has been shown in previous investigations, a GvHR may not develop in the case of strong rejection reactions. In this situation, rejection predominates. Therefore, we investigated rejection after orthotopic small-bowel transplantation and tried to elaborate the patterns of T cell infiltration in the graft in order to characterize the course of rejection without immunosuppression and during administration of cyclosporine A (CsA).

The Immunoscore® assay for Colon Cancer (IS Colon) is the first standardized immune-based assay for the classification of cancer. It assesses the host immune response to Colon Cancer (CC) by measuring intra- and peri-tumoral T cell infiltration in formalin-fixed paraffin-embedded (FFPE) tissue

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) of presumed autoimmune origin. On the basis of the pathophysiology of MS, inflammatory reactions in the CNS are considered detrimental. Recent evidence suggests that the injured CNS can also benefit from immune activity. In this review, we will first provide an overview of the mechanisms by which immune cells contribute to CNS injury in MS. We will further review evidence supporting a neuroprotective role of CNS inflammation with special focus on the protective properties of autoimmune reactions. Finally, we discuss the proposed mechanisms by which autoreactive T cells exert protection in the CNS and how this protection is regulated.