@phdthesis{Kleen2003, author = {Kleen, Thomas Oliver}, title = {Dissociated expression of granzyme B and IFN-gamma by T lymphocytes in HIV-1 infected individuals and its implications for Tc1 effector diversity}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-8460}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2003}, abstract = {A CD8+ cell-mediated host defense relies on cognate killing of infected target cells and on local inflammation induced by the secretion of IFN-g. Using assays of single cell resolution, it was studied to what extent these two effector function of CD8+ cells are linked. Granzyme B (GzB) is stored in cytolytic granules of CD8+ cells and its secretion is induced by antigen recognition of these cells. Following entry into the cytosol GzB induces apoptosis in the target cells. It was measured whether GzB release by individual CD8+ cells is accompanied by the secretion of IFN-gƒnƒnand of other cytokines. HIV peptide libraries were tested on bulk peripheral blood mononuclear cells and on purified CD4+ and CD8+ cells obtained from HIV infected individuals. The library included a panel of previously defined HLA class I restricted HIV peptides and an overlapping 20-mer peptide-series that covered the entire gp120 molecule. To characterize the in vivo differentiation state of the T-cells, freshly isolated lymphocytes were tested in assays of 24h duration. The data showed that only ~20\% of the peptides triggered the release of both GzB and IFN-g from CD8+ cells. The majority of the HIV peptides induced either GzB or IFN-g, ~40\% in each category. The GzB positive, IFN-g negative CD8+ cells did not produce IL-4 or IL-5, which suggests that they do not correspond to Tc2 cells but represent a novel Tc1 subclass, which was termed Tc1c. Also the IFN-g positive, GzB negative CD8+ cell subpopulation represents a yet undefined CD8+ effector cell lineage that was termed Tc1b. Tc1b and Tc1c cells are likely to make different, possibly antagonistic contributions to the control of HIV infection. Since IFN-g activates HIV replication in latently infected macrophages, the secretion of this cytokine by Tc1b cells in the absence of killing may have adverse effects on the host defense. In contrast, cytolysis by Tc1c cells in the absence of IFN-g production might represent the protective class of response. Further studies in the field of Tc1 effector cell diversity should lead to valuable insights for management of infections and developing rationales for vaccine design.}, subject = {Antigen CD8}, language = {en} } @article{KasangKalluvyaMajingeetal.2016, author = {Kasang, Christa and Kalluvya, Samuel and Majinge, Charles and Kongola, Gilbert and Mlewa, Mathias and Massawe, Irene and Kabyemera, Rogatus and Magambo, Kinanga and Ulmer, Albrecht and Klinker, Hartwig and Gschmack, Eva and Horn, Anne and Koutsilieri, Eleni and Preiser, Wolfgang and Hofmann, Daniela and Hain, Johannes and M{\"u}ller, Andreas and D{\"o}lken, Lars and Weissbrich, Benedikt and Rethwilm, Axel and Stich, August and Scheller, Carsten}, title = {Effects of Prednisolone on Disease Progression in Antiretroviral-Untreated HIV Infection: A 2-Year Randomized, Double-Blind Placebo-Controlled Clinical Trial}, series = {PLoS One}, volume = {11}, journal = {PLoS One}, number = {1}, doi = {10.1371/journal.pone.0146678}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146479}, pages = {e0146678}, year = {2016}, abstract = {Background HIV-disease progression correlates with immune activation. Here we investigated whether corticosteroid treatment can attenuate HIV disease progression in antiretroviral-untreated patients. Methods Double-blind, placebo-controlled randomized clinical trial including 326 HIV-patients in a resource-limited setting in Tanzania (clinicaltrials.gov NCT01299948). Inclusion criteria were a CD4 count above 300 cells/μl, the absence of AIDS-defining symptoms and an ART-na{\"i}ve therapy status. Study participants received 5 mg prednisolone per day or placebo for 2 years. Primary endpoint was time to progression to an AIDS-defining condition or to a CD4-count below 200 cells/μl. Results No significant change in progression towards the primary endpoint was observed in the intent-to-treat (ITT) analysis (19 cases with prednisolone versus 28 cases with placebo, p = 0.1407). In a per-protocol (PP)-analysis, 13 versus 24 study participants progressed to the primary study endpoint (p = 0.0741). Secondary endpoints: Prednisolone-treatment decreased immune activation (sCD14, suPAR, CD38/HLA-DR/CD8+) and increased CD4-counts (+77.42 ± 5.70 cells/μl compared to -37.42 ± 10.77 cells/μl under placebo, p < 0.0001). Treatment with prednisolone was associated with a 3.2-fold increase in HIV viral load (p < 0.0001). In a post-hoc analysis stratifying for sex, females treated with prednisolone progressed significantly slower to the primary study endpoint than females treated with placebo (ITT-analysis: 11 versus 21 cases, p = 0.0567; PP-analysis: 5 versus 18 cases, p = 0.0051): No changes in disease progression were observed in men. Conclusions This study could not detect any significant effects of prednisolone on disease progression in antiretroviral-untreated HIV infection within the intent-to-treat population. However, significant effects were observed on CD4 counts, immune activation and HIV viral load. This study contributes to a better understanding of the role of immune activation in the pathogenesis of HIV infection.}, language = {en} }