Search results for "Lymphocyte"

Tumor Recognition by the Cellular Immune System: New Aspects of Tumor Immunology

1997

Pathological role of IL-6 in the experimental allergic bronchial asthma in mice.

2005

Although allergic asthma was described to be associated with the presence of mucosal T helper (Th)2 cells, it is not entirely clear which factors are responsible for priming of T cells to differentiate into Th2 effector cells in this disease. Interleukin (IL)-6 has been recognized as important because it is secreted by cells of the innate immunity and induces the expansion of the Th2 effector cells, which are major players of the adaptive immune responses. Additionally, IL-6 released by dendritic cells (DCs) inhibits the suppressive function of CD4+CD25+ T regulatory cells, thus inhibiting the peripheral tolerance. The signal transduction of IL-6 has recently taught us how this cytokine inf…

Targeting p53, hdm2, and CD19: vaccination and immunologic strategies.

2000

Peptides presented by class I major histocompatibility complex (MHC) molecules and derived from normal self-proteins that are expressed at elevated levels by cells from a variety of human (Hu) malignancies provide, in theory, potential target antigens for a broad-spectrum, cytotoxic T lymphocyte (CTL)-based immunotherapy of cancer and hematologic malignancies. However, as such tumor- and leukemia-associated self-proteins are also expressed at low levels in some types of normal tissues, such as thymus, spleen and lymphohemopoietic cells, these self-MHC-self-peptide complexes may also represent thymic and/or peripheral tolerogens, thereby preventing immune responses. This is particularly true…

Proteasome-inhibited dendritic cells demonstrate improved presentation of exogenous synthetic and natural HLA-class I peptide epitopes.

2004

The design and successful clinical implementation of cancer vaccines targeting the induction of T-cell mediated immunity is a rapidly evolving field that is hampered by an empirical selection of antigen and adjuvant. In particular, vaccines using defined tumor-associated peptide epitopes elicit only a restricted T-cell repertoire in a minority of patients. In this regard, vaccines comprising the whole spectrum of antigens presented by individual autologous tumors would be advantageous. In an in vitro model, we evaluated the capacity of naturally processed Epstein-Barr virus-transformed B-lymphoblastoid-cell line (LCL)-derived peptides to activate virus-specific CD8+ T cells of seropositive …

Separation of T-cell-stimulating activity from streptococcal M protein

1992

The superantigenic properties of M protein type 5 of Streptococcus pyogenes have been implicated as an important pathogenicity factor in streptococcal autoimmune diseases. Here we show that after a single purification step by affinity chromatography on immobilized albumin or fibrinogen, M protein has no mitogenic activity for T cells. We demonstrate that the superantigenicity of M proteins of type 5 and type 1 is due to contamination with the highly potent pyrogenic exotoxins of S. pyogenes in the range of 0.1 to 0.01%. These results raise a general caveat for work with these extremely active T-cell mitogens, because the mitogenicity of other streptococcal or staphylococcal proteins could b…

Stress protein/peptide complexes derived from autologous tumor tissue as tumor vaccines.

1999

Vaccination of inbred mice with tumor-derived stress proteins hsp70, hsp90, and gp96/grp94 elicits a protective immunity to the tumor from which the vaccine was purified. There is now comprehensive experimental evidence that the antigenicity of tumor-derived hsp70, hsp90, and gp96 preparations results from diverse arrays of endogenous peptide antigens complexed with these stress proteins. Vaccination with tumor-derived stress protein/peptide complexes leads to their uptake and processing by professional antigen-presenting cells and to presentation of associated tumor peptide antigens to cytotoxic T cells. This induces a tumor-specific cytotoxic T cell response. The attractiveness of the con…

The enemy in you: the interdependency of the localisation and antigenicity of proteins

2009

The subcellular localisation of protein components should be important for their antigenicity. This assumption is derived from the concept of MHC restriction, where CD4 and CD8 T lymphocytes can only interact with MHC II and MHC I surface receptors, respectively. If this mechanism applies, however, then intracellular components should have immunogenic effects mediated by MHC II and CD4 T lymphocytes as soon as they enter the extracellular space. Conversely, extracellular components should generate an immune response that is mediated by MHC I and CD8 lymphocytes when they breach the intracellular space and when they exceed a critical concentration. In this study, these hypotheses were invest…

Stimulation of human T cells by microbial 'superantigens'.

1991

The enterotoxins and the TSST of S. aureus, the erythrogenic toxins A and C of S. pyogenes and a still uncharacterized exoprotein of M. arthritidis belong to a family of exotoxins that have in common a potent mitogenic activity for T lymphocytes of several species. These proteins stimulate CD4+ and C8+ T cells, as well as a fraction of gamma delta TCR-bearing T cells by cross-linking variable parts of the T cell antigen receptor with MHC class II molecules on accessory or target cells. They are functionally bivalent molecules having distinct interaction sites for variable parts of the TCR and for nonpolymorphic parts of the MHC class II molecule. For alpha beta TCR-bearing T cells the V bet…

Embryonic neural cell adhesion molecules on human natural killer cells

1989

The neural cell adhesion molecules (NCAM) are surface glycoproteins that were first described in brain tissue. NCAM mediate adhesion in a variety of cell-cell interactions. In the present study we show that the so-called "embryonic" NCAM, i.e., the highly polysialylated forms of these proteins, are expressed on natural killer cells and some CD3+ cells in man. Homotypic binding of NCAM, believed to be of importance for cell-cell adhesion in neural tissues, appears not to be essential for NK cell-mediated killing. Yet, NCAM might be involved in NK cell migration, homing or related functions.

Requirements for the growth of TH1 lymphocyte clones.

1990

Besides the signal generated in a T lymphocyte after triggering the T cell receptor (TcR), most lymphocytes need a "second signal" to become fully activated. The necessity and nature of the "second signal" differs between different types of T cells. At the level of CD4-positive T helper lymphocytes interleukin 1 (IL 1) serves as "second signal" for those of the TH2 subtype (IL4, 5, 6 producer) but not for those of the TH1 subtype (IL 2, IFN-gamma producer). This correlates with the absence of the IL 1 receptor at the surface of TH1 clones. We report herein the further purification of T cell stimulating factor (TSF), a soluble mediator involved in the proliferation of TH1 lymphocytes. A prep…