Search results for "G cell"

The number of intratumoral dendritic cells and ?-chain expression in T cells as prognostic and survival biomarkers in patients with oral carcinoma

2001

BACKGROUND Dendritic cells (DCs) are antigen-presenting cells with a unique ability to cross prime T cells and generate strong antitumor responses. This study evaluates the presence and prognostic significance of DCs as well as functional T cells, which accumulate in the microenvironment in patients with oral squamous cell carcinoma (OSCC). METHODS Immunohistochemistry for S-100 positive or p55 positive DCs and for T-cell receptor (TcR)-associated ζ-chain expression in tumor-infiltrating lymphocytes (TILs) was performed in 132 paraffin embedded specimens from patients with primary OSCC. The median clinical follow-up for the patients was 50 months. The numbers of intratumoral DCs or TILs exp…

Naturally processed and HLA-B8-presented HPV16 E7 epitope recognized by T cells from patients with cervical cancer.

2004

Several major histocompatibility complex (MHC) alleles have been reported to present peptides derived from the HPV16 E7 oncoprotein to T cells. We describe an overrepresentation of the HLA-B8 allele (28.44%) in cervical cancer patients as compared to the MHC class I allele frequency in a local healthy control population (18.80%) and the identification of an HLA-B8-binding peptide TLHEYMLDL (HPV16 E77–15), which is able to drive HPV16 E7-specific and MHC class I-restricted T-cell responses in peripheral blood lymphocytes from healthy individuals. TLHEYMLDLspecific T cells recognize the naturally processed and presented peptide on HPV16 cervical cancer cells transfected with the HLA-B8 gene d…

Generation of CD8+T cells expressing two additional T-cell receptors (TETARs) for personalised melanoma therapy

2015

Adoptive T-cell therapy of cancer often fails due to the tumor cells' immune escape mechanisms, like antigen loss or down-regulation. To anticipate immune escape by loss of a single antigen, it would be advantageous to equip T cells with multiple specificities. To study the possible interference of 2 T-cell receptors (TCRs) in one cell, and to examine how to counteract competing effects, we generated TETARs, CD8(+) T cells expressing two additional T-cell receptors by simultaneous transient transfection with 2 TCRs using RNA electroporation. The TETARs were equipped with one TCR specific for the common melanoma antigen gp100 and one TCR recognizing a patient-specific, individual mutation of…

Regulation of CD1d expression by murine tumor cells: escape from immunosurveillance or alternate target molecules?

2002

alpha beta+ TCR T cells recognize peptide fragments displayed by MHC-class I or -class II molecules. Recently, additional mechanisms of antigen recognition by T cells have been identified, including CD1-mediated presentation of nonpeptide antigens. Only a limited number of CD1 antigens is retained in the mouse, i.e., the group II CD1 antigens, which are split into CD1D1 and CD1d2. Several T cell subsets have been shown to interact with murine CD1 antigens, including NK cells or "natural T cells" with the invariant V alpha 14 J alpha 281 TCR chain. Even if TAP defects may prevent classical endogenous antigen presentation in tumor cell lines, antigen presentation via CD1 is still functional. …

Blockade of PD-L1 (B7-H1) augments human tumor-specific T cell responsesin vitro

2006

Human tumors frequently escape immune destruction, despite the presence of cytotoxic T cells (CTL) recognizing tumor-associated antigens (TAA). We have previously shown that programmed death ligand-1 (PD-L1), a recently identified ligand of the B7 superfamily, is expressed on murine tumors and can inhibit antitumor immune responses. To evaluate the clinical relevance of our animal model findings, we examined human tumors and tumor-specific T cells. We found PD-L1 to be constitutively expressed on human renal cell carcinoma (RCC) cell lines and upregulated on human melanoma cell lines upon exposure to interferon-gamma. Similarly, we found binding of anti-PD-L1 monoclonal antibody (mAb) on fr…

Dendritic cells as mediators of tumor-induced tolerance in metastatic melanoma.

1997

Escape from immune surveillance is critical for tumor progression in metastatic melanoma. We assessed the function of melanoma-derived dendritic cells (DCs) in patients presenting simultaneously with responding (rM) or progressing (pM) melanoma metastases. These rare coincidences allowed us to compare syngeneically the function of tumor DCs. CD83+ DCs were purified freshly from large responding (rDCs) or progressing (pDCs) metastases following chemo-immunotherapy. rDCs were 5 times more potent inducers of allogeneic T-cell proliferation than the pDCs that were used as control. Phenotypic analysis showed a marked depression of CD86 expression on pDCs. Culture supernatants from pM showed prod…

2004

Tumor-reactive T cells play an important role in cancer immunosurveillance. Applying the multimer technology, we report here an unexpected high frequency of Melan-A-specific CTLs in a melanoma patient with progressive lymph node metastases, consisting of 18 and 12.8% of total peripheral blood and tumor-infiltrating CD8+ T cells, respectively. Melan-A-specific CTLs revealed a high cytolytic activity against allogeneic Melan-A-expressing target cells but failed to kill the autologous tumor cells. Loading of the tumor cells with Melan-A peptide reversed the resistance to killing, suggesting impaired function of the MHC class I antigen processing and presentation pathway. Mutations of the codin…

2004

Address: 1I. Medical Department, University of Mainz, Langenbeckstr.1, D-55101 Mainz, Germany, 2Deutsches Krebsforschungszentrum, Applied Tumor Virology, Dept. F0100, and Institut National de la Sante et de la Recherche Medicale Unite 375, Im Neuenheimer Feld 242, D-69120 Heidelberg, Germany, 3III. Medical Department, University of Mainz, Langenbeckstr.1, D-55101 Mainz, Germany and 4Med. Department Mitte, Klinikum Dortmund GmbH, Beurhausstr. 10, 44137 Dortmund, Germany

Dendritic cell-tumor cell hybrids and immunotherapy: what's next?

2011

Dendritic cells (DC) are professional antigen-presenting cells currently being used as a cellular adjuvant in cancer immunotherapy strategies. Unfortunately, DC-based vaccines have not demonstrated spectacular clinical results. DC loading with tumor antigens and DC differentiation and activation still require optimization. An alternative technique for providing antigens to DC consists of the direct fusion of dendritic cells with tumor cells. These resulting hybrid cells may express both major histocompatibility complex (MHC) class I and II molecules associated with tumor antigens and the appropriate co-stimulatory molecules required for T-cell activation. Initially tested in animal models, …

Sjögren's autoimmunity: how perturbation of recognition in endomembrane traffic may provoke pathological recognition at the cell surface

1998

CD4 T cell antigen recognition requires presentation by major histocompatibility complex Class II molecules (MHC II). B cell surface immunoglobulins recognize antigens independently of MHC II, but activation typically requires CD4 cell cytokines as accessory signals. Plasma membrane-endomembrane traffic in lacrimal gland acinar cells, targets of autoimmune activity in Sjogren's syndrome, may satisfy both requirements. The Golgi protein galactosyltransferase and the lysosomal proteins cathepsin B and cathepsin D appear at the plasma membranes during sustained secretomotor stimulation. The RNA transcription termination factor La, a frequent target of Sjogren's autoantibodies, appears in the a…