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Background. Limited data exist describing the clinical outcome and immunological response primed during simultaneously acquired acute hepatitis C virus (HCV) and human immunodeficiency virus (HIV) coinfection. We present detailed clinical and immunological analysis of 3 individuals after concomitant infection with acute HCV and primary HIV. Methods. In addition to longitudinal clinical parameters, virus-specific T cell responses were assessed using Elispot, standard proliferative (carboxyfluorescein diacetate succinimidyl ester), and in vitro CD4+ T cell assays. Results. In all patients, anti-HCV treatment was started with pegylated interferon-α, and antiretroviral therapy was coadministered early during primary infection. HCV viremia was cleared under therapy with pegylated interferon- a in all 3 cases. In 2 patients, HIV replication was contained even after antiretroviral therapy had been interrupted, which was associated with strong HIV-specific CD8+ and CD4+ T cell responses. In these 2 patients, multispecific HCV CD4+ T cell responses could also be detected. No HCV-specific CD4+ T cell responses were detected in the third patient, who also had the lowest nadir CD4+ cell count during primary HIV infection (<200 cells/μL). Conclusions. Anti-HIV and -HCV therapy should be considered early in cases of concomitant acute HCV and HIV coinfection, because succcessful therapy of HCV viremia seems possible even during primary HIV infection. HCV-specific T cell immunity is generated during primary HIV infection and can be preserved by HCV treatment. However, the optimal treatment algorithm needs to be established in prospective, randomized trials. [ABSTRACT FROM AUTHOR]

Background: Interleukin-12 (IL-12) is well characterized to induce cellular antitumoral immunity by activation of NK-cells and T-lymphocytes. However, systemic administration of recombinant human IL-12 resulted in severe toxicity without perceptible therapeutic benefit. Even though intratumoral expression of IL-12 leads to tumor regression and long-term survival in a variety of animal models, clinical trials have not yet shown a significant therapeutic benefit. One major obstacle in the treatment with IL-12 is to overcome the relatively low expression of the therapeutic gene without compromising the safety of such an approach. Our objective was to generate an adenoviral vector system enabling the regulated expression of very high levels of bioactive, human IL-12. Results: High gene expression was obtained utilizing the VP16 herpes simplex transactivator. Strong regulation of gene expression was realized by fusion of the VP16 to a tetracycline repressor with binding of the fusion protein to a flanking tetracycline operator and further enhanced by auto-regulated expression of its fusion gene within a bicistronic promoter construct. Infection of human colon cancer cells (HT29) at a multiplicity of infection (m.o.i.) of 10 resulted in the production of up to 8000 ng/106 cells in 48 h, thus exceeding any published vector system so far. Doxycycline concentrations as low as 30 ng/ml resulted in up to 5000-fold suppression, enabling significant reduction of gene expression in a possible clinical setting. Bioactivity of the human single-chain IL-12 was similar to purified human heterodimeric IL-12. Frozen sections of human colon cancer showed high expression of the coxsackie adenovirus receptor with significant production of human single chain IL-12 in colon cancer biopsies after infection with 3*107 p.f.u. Ad.3r-scIL12. Doxycycline mediated suppression of gene expression was up to 9000-fold in the infected colon cancer tissue. Conclusion: VP16 transactivator-mediated and doxycycline-regulated expression of the human interleukin-12 gene enables highly efficient and tightly controlled cytokine expression in human cancer. These data illustrate the potential of the described adenoviral vector system for the safe and superior expression of therapeutic genes in the treatment of colorectal cancer and other malignancies. [ABSTRACT FROM AUTHOR]

The immunological and virological impact of short-term treatment initiated during acute human immunodeficiency virus type 1 (HIV-1) infection was assessed prospectively in 20 subjects, 12 of whom initiated highly active antiretroviral therapy (HAART) for 24 weeks and then terminated treatment. Treatment resulted in suppression of viremia, an increase in the CD4+ T cell count, enhanced differentiation of HIV-1-specific CD8+ T cells from effector memory to effector cells at week 24 of HAART, and significantly higher virus-specific interferon-γ+ CD8+ T cell responses after viral rebound (at week 48). However, despite these immunological changes, no differences in viremia or in the CD4+ T cell count were found 6 months after HAART was stopped, when treated subjects were compared with untreated subjects. [ABSTRACT FROM AUTHOR]

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