In higher vertebrates, mineralo-(aldosterone) and glucocorticoids (cortisol/corticosterone) exert their multiple actions via specific transcription factors, glucocorticoid (GR) and mineralocorticoid (MR) receptors. Teleostean fishes lack aldosterone and mineral regulatory processes seem under dominant control by cortisol. Despite the absence of the classical mineralocorticoid aldosterone, teleostean fishes do have an MR with cortisol and possibly 11-deoxycorticosterone (DOC) (as alternative for aldosterone) as predominant ligands. We studied corticoid receptors in common carp (Cyprinus carpio L). Through homology cloning and bioinformatic analysis, we found duplicated GR genes and a single MR gene. The GR genes likely result from a major genomic duplication event in the teleostean lineage; we propose that the gene for a second MR was lost.Transactivation studies show that the carp GRs and MR have comparable affinity for cortisol; the MR has significantly higher sensitivity to DOC, and this favours a role for DOC as MR ligand in fish physiology. mRNA of the GRs and the MR is expressed in forebrain (in pallial areas homologous to mammalian hippocampus), corticotrophin-releasing hormone (CRH) cells in the pre-optic nucleus (NPO) and pituitary pars distalis ACTH cells, three key neural/endocrine components of the stress axis. After exposure to prolonged and strong (not to mild acute) stressors, mRNA levels of both GRs and MR become down-regulated in the brain, but not in the NPO CRH cells or pituitary ACTH cells. Our data predicts a function in stress physiology for all CRs and suggest telencephalon as a first line cortisol target in stress.

Type I interferons have been typically studied for their effects in the context of bacterial or viral infections. However in this report, we provide evidence that Interferon-alpha (IFN-α) expressing cells are present in the thymus in the absence of infection. We show that pDC express the highest level of IFN-α and that MxA, which is exclusively expressed after engagement of the type I IFN receptor by IFN-α/β, is expressed in normal fetal and post-natal thymus, but not in the periphery. The highest level of MxA is expressed in mature thymocytes and pDC located in the medulla and at the cortico-medullary junction. The anti-microbial peptide LL-37, which is expressed in the thymus, when complexed with eukaryotic nucleic acids, induces the secretion of IFN-α by thymic pDC. This results in the upregulation of MxA expression in responsive thymocytes. We propose that the secretion of IFN-α in the thymus may function to regulate the rate of T cell development and modulate the requirements for the selection of developing T cells.

Strategies of manipulating immunosuppressive regulatory T cells (Treg) in cancer patients are currently evaluated in clinical trials. Treg suppress immune responses of tumor-specific T cells; yet, relatively little is known about the impact of Treg on innate immune cells in tumor models in vivo. Many tumors lose expression of MHC class I. Therefore, our study aimed at defining strategies to strengthen immune responses against a high tumor burden of the MHC class I-deficient mouse lymphoma RMA-S. We demonstrate that Treg depletion in mice led to tumor rejection that was dependent on T cells, NK cells and IFN-c. In the absence of Treg elevated levels of IFN-c were produced by tumor-infiltrating T cells and NK cells. Tumor rejection observed in the absence of Treg correlated with a substantial IFN-c-dependent increase in the numbers of tumorinfiltrating leukocytes. The most abundant cell population in the tumors was macrophages. Tumor-infiltrating macrophages from Treg-depleted mice expressed increased amounts of MHC class II, produced highly enhanced levels of pro-inflammatory cytokines and inhibited tumor cell proliferation. It was reported that tumor-infiltrating macrophages have multi-faceted functions promoting or counteracting tumor growth. In our study, high numbers of macrophages infiltrating RMA-S tumors in the absence of Treg correlated with tumor rejection suggesting that macrophages are additional targets for Treg-mediated immune suppression in cancer.

Out of all malignancies, breast cancer resembles the most common malignant caner type (26%) of women in the western world and the second most frequent cancer related cause of death (15%) in women. Efficient treatment options are available for early stage breast cancers yielding five year survival rates of up to 85%, however for metastasized breast cancer types, five year survival rates are resided at much lower levels (20%) and therapy options are very limited. It is therefore of great importance to establish innovative therapy strategies which will affect the late stage breast cancer tumors. Immunotherapy approaches, particularly adoptive T cell transfer, constitute an attractive strategy to develop new therapy options for metastasized mammary carcinomas. The differentiation antigen NY-BR-1 was found to be expressed on mRNA level in breast tissue, testis, prostate, and most notably in 80% of tested breast cancers. Among normal tissues, expression of the NY-BR-1 protein was present solely in ductal epithelium of the breast. Compared to healthy breast tissue NY-BR-1 protein levels are highly elevated in invasive breast tumors and their corresponding metastasis. Thus, NY-BR-1 can be considered as a breast cancer associated tumor antigen that might represent a suitable target antigen for T cell based immunotherapy approaches. The main focus of this project is to identify novel HLA-restricted T cell epitopes that could be used in clinical trials. Therefore, various HLA-transgenic (tg) mouse strains (DR4tg, DR3tg and HHDtg mice), were immunized with the NY-BR-1- encoding expression plasmid pcDNA3.1-NY-BR-1 followed by ex vivo analyses of the NY-BR-1-specific T cell responses with a synthetic peptide library covering the entire NY-BR-1 protein. Applying this strategy, four potential HLA-DRB1*0301 restricted epitopes and three HLA-DRB*0401 restricted candidate epitopes could be determined. The relevance of these new epitopes for the human system will be analyzed by screening of PBMCs from tumor patients and healthy donors for the presence of cognate T cells. Such T cells will be expanded and used as donors for high affinity NY-BR-1-specific TCRs in order to establish autologous TCR-transduced T cells ready for adoptive transfer of breast cancer patients. Currently, blood-samples of NY-BR-1+ patients are being collected for subsequent in vitro analyses of HLA-restricted, NY-BR-1-specific T cell responses. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1581. doi:1538-7445.AM2012-1581