A combination of soluble helper factors bypasses the requirement for stimulator cells and induces nonspecific cytotoxic T cell responses

The specificity of cytotoxic T lymphocyte (CTL) responses generated in the presence of lymphokines was studied. Thymic responder cells were activated in the presence of stimulator cells that differed in their metabolic activity. After 5 days of culture, the cytotoxic response was estimated in a 4-h 51Cr-release test. Coculture of thymic responders with irradiated splenic stimulator cells in the presence of interleukin 2(IL 2) led to preferential cytolysis of target cells that expressed the same histocompatibility antigens as the cells used for sensitization. Addition of T cell cytotoxicity-inducing factor 1 (TCF1), however, to those cultures made the presence of stimulator cells unnecessary and induced cytotoxic responses against all target cells tested, including target cells syngeneic to the responder cells. This activation was neither due to contaminating mitogen nor to the effect of heterologous serum in the assay system. The conclusion of these findings was that either polyclonal activation of CTL was induced by TCF1 or that some specific CTL clones differentiated into unrestricted killer cells under the influence of TCF1

Capacity of different cell types to stimulate cytotoxic T lymphocyte precursor cells in the presence of interleukin 2

Plastic-adherent cells enriched for dendritic cells (AC) were found to be among the most potent stimulator cells for the activation of cytotoxic T lymphocytes (CTL) in vitro in the presence of interleukin 2 (IL 2) and a constant second set of allogeneic stimulator cells. Concanavalin A-activated nylon wool-nonadherent spleen cells ( CNWT ), concanavalin A-activated unfractionated spleen cells ( Cspl ), and some variants of the ESb T lymphoma line were equally effective as stimulator cells, however, and provoked a substantial cytotoxic response at concentrations of 10(4) cells per culture or less. In contrast, nonactivated nylon wool-nonadherent spleen cells ( NWT ) or unfractionated spleen cells (Spl) and cells of the P815 mastocytoma, the Meth A fibrosarcoma, and the T cell lymphomas Ly 5178 Eb and ESb did not stimulate cytotoxic responses at these cell concentrations. The strong stimulatory potential of the Cspl preparation was reduced by treatment with anti-Thy-1 antibody plus complement, whereas the stimulatory activity of the AC preparation was resistant to this treatment. All cell types tested expressed class I major histocompatibility antigens. Nonactivated NWT cells, in contrast to the CNWT preparation, showed no detectable staining with anti-I-E or anti-I-A antibodies and also a slightly weaker staining with class I antisera. Experiments with the tumor cell lines revealed, however, that there was no strict correlation between stimulatory potential and density of class I alloantigens or the expression of I-E determinants. Experiments on primary cytotoxic responses in vivo gave similar results. Experiments in cultures with a single set of stimulator cells and I region-compatible responder cells indicated that AC and Cspl or CNWT also have a markedly stronger capacity than NWT to induce IL 2-dependent DNA synthesis

Induction of IL 2 receptor expression and cytotoxicity of thymocytes by stimulation with TCF1

We investigated the role of T cell cytotoxicity inducing factor 1 (TCF1) in the induction of a cytotoxic T cell response. We found that help-deficient thymocyte cultures supplied with saturating amounts of purified IL 2 did not develop CTL in a 5-day culture. The expression of cytotoxicity was dependent on the addition of TCF1 derived from the T cell hybridoma K15. TCF1 also induced proliferation of thymocytes in the presence of IL 2. Only the PNA- thymocyte subpopulation responded to TCF1 with proliferation and cytotoxicity in the presence of IL 2. The monokine IL 1 also induced proliferation in this subpopulation but failed to induce cytotoxicity. IL 1 was further distinguished from TCF1 by inhibition of IL 1-induced but not TCF1-induced proliferation by anti-IL 1 antibodies. In addition, using anti-IL 2 receptor antibodies (AMT 13), we showed that TCF1 in the presence of IL 2 substantially increased IL 2 receptor expression in thymocytes. IL 1 had the same effect on induction of IL 2 receptor expression as TCF1. Because some effects of IL 1 and TCF1 are distinct and some overlap, we discuss whether IL 1 and TCF1 induce different subsets of PNA- thymocytes

KliWES - Nebelkorrektur

Nebel, Tau, Reif, Raureif und Raufrost können mit den üblichen Verfahren der Niederschlagsmessung nicht erfasst werden. Dies ist besonders in der Erzgebirgsregion problematisch. Es wurde daher eine Niederschlagskorrektur für Sachsen erarbeitet. Mit dieser Methode kann der abgesetzte bzw. abgefangene Niederschlag quantifiziert und ein bilanzreiner Wasserhaushalt berechnet werden. Die nebelkorrigierten Daten stehen im Wasserhaushaltsportal Sachsen zur Verfügung. Die Untersuchung erfolgte im Rahmen des Projektes KliWES – Klimawandel und Wasserhaushalt

Klimawandel und Wasserhaushalt in Sachsen

Nach Abschluss des KliWES-Teilprojektes »Säule B – ArcEGMO« liegen sachsenweite Wasserhaushaltsdaten für den Ist-Zustand (1961–2010) und ausgewählte Zukunftsszenarien (2011–2100) des Klimas und der Landnutzung vor. Der vorliegende Bericht ergänzt die als interaktive Karten erfolgte Veröffentlichung von Projektergebnissen im Wasserhaushaltsportal Sachsen. Diese sollen vorrangig Umweltverwaltungen, wissenschaftliche Einrichtungen sowie Ingenieur- und Planungsbüros bei der Bearbeitung regionaler Fragestellungen der Anpassung an Klimawandelfolgen unterstützen

CMS physics technical design report : Addendum on high density QCD with heavy ions

Peer reviewe

Activation of cytotoxic T lymphocytes requires at least two spleen cell-derived helper factors besides interleukin 2

The dependency of induction of T cell cytotoxicity on lymphokines was studied. 1 X 10(5) nylon wool-purified thymic lymphocytes or 10(4) spleen cells were cultured with TNP-haptenated syngeneic UV-irradiated spleen cells in the presence of a variety of lymphokine preparations. Concanavalin A-induced spleen cell supernatants mediated strong cytotoxic responses in this system. Three other preparations, namely, a partially purified IL 2 preparation from PMA-stimulated EL-4 thymoma cells, a Con A-induced spleen cell supernatant that was absorbed with an IL 2-dependent cell line, and a Con A-induced supernatant that was dialyzed at pH 2 were all ineffective in mediating a cytotoxic response. In reconstitution experiments, cytotoxic responses were only obtained when either the absorbed preparation or the pH 2-treated preparation was mixed with the IL 2 preparation from EL-4 cells. No reconstitution occurred after mixing of the absorbed with the pH 2-treated preparation. pH 2 treatment of the absorbed preparation did not abolish its synergistic effect when added to the IL 2 preparation from EL-4 cells. These results led to the conclusion that activation of cytotoxic lymphocyte precursors requires at least two other lymphokines in addition to IL 2. One T cell cytotoxicity-inducing factor (TCF1) remained in Con A-induced supernatants after absorption with IL 2 receptor-bearing T cell line cells. It was pH 2-resistant and was not found in EL-4 supernatants. A second T cell cytotoxicity-inducing factor (TCF2) was pH 2-sensitive and was found in Con A-induced spleen cell supernatants as well as in interferon-free supernatants of PMA-stimulated EL-4 cells. This activity co-purified with IL 2. It was absorbed by the IL 2-dependent T cell line together with IL 2. IL 2 differs from TCF2 since it is pH 2-resistant