Antigen-specific, antibody-coated, exosome-like nanovesicles deliver suppressor T-cell microRNA-150 to effector T cells to inhibit contact sensitivity

Background: T-cell tolerance of allergic cutaneous contact sensitivity (CS) induced in mice by high doses of reactive hapten is mediated by suppressor cells that release antigen-specific suppressive nanovesicles. Objective: We sought to determine the mechanism or mechanisms of immune suppression mediated by the nanovesicles. Methods: T-cell tolerance was induced by means of intravenous injection of hapten conjugated to self-antigens of syngeneic erythrocytes and subsequent contact immunization with the same hapten. Lymph node and spleen cells from tolerized or control donors were harvested and cultured to produce a supernatant containing suppressive nanovesicles that were isolated from the tolerized mice for testing in active and adoptive cell-transfer models of CS. Results: Tolerance was shown due to exosome-like nanovesicles in the supernatants of CD81 suppressor T cells that were not regulatory T cells. Antigen specificity of the suppressive nanovesicles was conferred by a surface coat of antibody light chains or possibly whole antibody, allowing targeted delivery of selected inhibitory microRNA (miRNA)–150 to CS effector T cells. Nanovesicles also inhibited CS in actively sensitized mice after systemic injection at the peak of the responses. The role of antibody and miRNA-150 was established by tolerizing either panimmunoglobulin-deficient JH2/2 or miRNA-1502/2 mice that produced nonsuppressive nanovesicles. These nanovesicles could be made suppressive by adding antigen-specific antibody light chains or miRNA-150, respectively. Conclusions: This is the first example of T-cell regulation through systemic transit of exosome-like nanovesicles delivering a chosen inhibitory miRNA to target effector T cells in an antigen-specific manner by a surface coating of antibody light chains

Patients without hepatocellular carcinoma progression after transarterial chemoembolization benefit from liver transplantation

AIM: To assess the outcome of patients, who underwent transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) and subsequently liver transplantation (OLT) irrespective of tumor size when no tumor progression was observed. METHODS: Records, imaging studies and pathology of 84 patients with HCC were reviewed. Ten patients were not treated at all, 67 patients had TACE and 35 of them were listed for OLT. Tumor progression was monitored by ultrasound and AFP level every 6 wk. Fifteen patients showed signs of tumor progression without transplantation. The remaining 20 patients underwent OLT. Further records of 7 patients with HCC seen in histological examination after OLT were included. RESULTS: The patients after TACE without tumor progression underwent transplantation and had a median survival of 92.3 mo. Patients, who did not qualify for liver transplantation or had signs of tumor progression had a median survival of 8.4 mo. The patients without treatment had a median survival of 3.8 mo. Independent of International Union Against Cancer (UICC) stages, the patients without tumor progression and subsequent OLT had longer median survival. No significant difference was seen in the OLT treated patients if they did not fulfill the Milan criteria. CONCLUSION: Selection of patients for OLT based on tumor progression results in good survival. The evaluation of HCC patients should not only be based on tumor size and number of foci but also on tumor progression and growth behavior under therapy. (c) 2007 The WJG Press. All rights reserved