JunB promotes Th17 cell identity and restrains alternative CD4+ T-cell programs during inflammation.

T helper 17 (Th17) cell plasticity contributes to both immunity and autoimmunity; however, the factors that control lineage flexibility are mostly unknown. Here we show the activator protein-1 (AP-1) factor JunB is an essential regulator of Th17 cell identity. JunB activates expression of Th17 lineage-specifying genes and coordinately represses genes controlling Th1 and regulatory T-cell fate. JunB supports Th17 cell identity by regulating key AP-1 complex constituents. In particular, JunB limits the expression of the subset repressor IRF8, and impedes access of JunD to regulatory regions of alternative effector loci. Although dispensable for homeostatic Th17 cell development, JunB is required for induction and maintenance of Th17 effector responses in the inflammatory contexts of both acute infection and chronic autoimmunity in mice. Through regulatory network analysis, we show that JunB is a core regulator of global transcriptional programs that promote Th17 cell identity and restrict alternative CD4+ T-cell potential.AP-1 family transcription factors regulate CD4+ T helper cell differentiation. Here the authors show that the AP-1 member JunB is a nonredundant regulator of transcriptional programs that support Th17 cell identity and restrain alternative Th1 and Treg cell fates in inflammatory contexts of acute fungal infection and chronic autoimmunity.

A neuron-specific cytoplasmic dynein isoform preferentially transports TrkB signaling endosomes.

Cytoplasmic dynein is the multisubunit motor protein for retrograde movement of diverse cargoes to microtubule minus ends. Here, we investigate the function of dynein variants, defined by different intermediate chain (IC) isoforms, by expressing fluorescent ICs in neuronal cells. Green fluorescent protein (GFP)-IC incorporates into functional dynein complexes that copurify with membranous organelles. In living PC12 cell neurites, GFP-dynein puncta travel in both the anterograde and retrograde directions. In cultured hippocampal neurons, neurotrophin receptor tyrosine kinase B (TrkB) signaling endosomes are transported by cytoplasmic dynein containing the neuron-specific IC-1B isoform and not by dynein containing the ubiquitous IC-2C isoform. Similarly, organelles containing TrkB isolated from brain by immunoaffinity purification also contain dynein with IC-1 but not IC-2 isoforms. These data demonstrate that the IC isoforms define dynein populations that are selectively recruited to transport distinct cargoes.

Immunological profiling of a panel of human ovarian cancer cell lines.

PURPOSE: The efficient identification of peptide antigens recognized by ovarian cancer-specific cytotoxic T lymphocytes (CTL) requires the use of well-characterized ovarian cancer cell lines. To develop such a panel of cell lines, 11 ovarian cancer cell lines were characterized for the expression of class I and class II major histocompatibility complex (MHC)-encoded molecules, 15 tumor antigens, and immunosuppressive cytokines [transforming growth factor beta (TGF-beta) and IL-10]. METHODS: Class I MHC gene expression was determined by polymerase chain reaction (PCR), and class I and class II MHC protein expression was determined by flow cytometry. Tumor antigen expression was determined by a combination of polymerase chain reaction (PCR) and flow cytometry. Cytokine expression was determined by ELISA. RESULTS: Each of the ovarian cancer cell lines expresses cytokeratins, although each cell line does not express the same cytokeratins. One of the lines expresses CD90, which is associated with a fibroblast lineage. Each of the cell lines expresses low to moderate amounts of class I MHC molecules, and several of them express low to moderate amounts of class II MHC molecules. Using a combination of PCR and flow cytometry, it was determined that each cell line expressed between six and thirteen of fifteen antigens tested. Little to no TGF-beta3 was produced by any of the cell lines, TGF-beta1 was produced by three of the cell lines, TGF-beta2 was produced by all of the cell lines, with four of the cell lines producing large amounts of the latent form of the molecule, and IL-10 was produced by one of the cell lines. CONCLUSIONS: Each of the 11 ovarian cancer lines is characterized by a unique expression pattern of epithelial/fibroblast markers, MHC molecules, tumor antigens, and immunosuppressive cytokines. Knowledge of these unique expression patterns will increase the usefulness of these cell lines in identifying the antigens recognized by ovarian cancer-specific CTL.

The TAG family of cancer/testis antigens is widely expressed in a variety of malignancies and gives rise to HLA-A2-restricted epitopes.

The TAG-1, TAG-2a, TAG-2b, and TAG-2c cancer/testis genes, known to be expressed in an unusually high percentage of melanoma cell lines, are shown here to be expressed in a variety of tumor lines of diverse histologic type, including cancers of the brain, breast, colon, lung, ovary, pharynx, and tongue. The genes are also expressed in fresh, uncultured melanoma, and ovarian cancer cells. Epitope prediction algorithms were used to identify potential HLA-A1, HLA-A2, HLA-A3, HLA-B7, and HLA-B8 epitopes, and these potential epitopes were tested for their ability to stimulate a peptide-specific cytotoxic T lymphocyte response using lymphocytes from healthy donors. Two HLA-A2-restricted epitopes (SLGWLFLLL and LLLRLECNV) were identified using this approach. Cytotoxic T lymphocytes specific for each of these peptides were capable of recognizing tumor cells expressing both the corresponding class I major histocompatibility complex encoded molecule and the TAG genes. These results indicate that TAG-derived peptides may be good components of a therapeutic vaccine designed to target melanoma and a variety of epithelial cell-derived malignancies.