Murine liver allograft transplantation: Tolerance and donor cell chimerism

Nonarterialized orthotopic liver transplantation with no immunosuppression was performed in 13 mouse‐strain combinations. Two strain combinations with major histocompatibility complex class I and class II and minor histocompatibility complex disparity had 20% and 33% survival of more than 100 days, but the other 11 combinations, including four that were fully allogeneic and all with only class I, class II or minor disparities, yielded 45% to 100% survival of more than 100 days. Long‐living recipients permanently accepted donor‐strain heterotopic hearts transplanted on the same day or donor‐strain skin 3 mo after liver transplantation, in spite of detectable antidonor in vitro activity with mixed lymphocyte reaction and cellmediated lymphocytotoxicity testing (split tolerance). In further donor‐specific experiments, liver grafts were not rejected by presensitized major histocompatibility complex class I‐disparate recipients and they protected donor‐strain skin grafts from second set (or any) rejection. Less frequently, liver transplantation rescued rejecting skin grafts placed 1 wk earlier in major histocompatibility complex class I, class II and minor histocompatibility complex, class II or minor histocompatibility complex‐disparate strain combinations. Donor‐derived leukocyte migration to the central lymphoid organs occurred within 1 to 2 hr after liver transplantation in all animals examined, persisted in the surviving animals until they were killed (>375 days), and was demonstrated with double‐immunolabeling to be multilineage. The relation of these findings to so‐called hepatic tolerogenicity and to tolerance in general is discussed. (HEPATOLOGY 1994;19:916–924.) Copyright © 1994 American Association for the Study of Liver Disease

Oxygenation inhibits the physiological tissue-protecting mechanism and thereby exacerbates acute inflammatory lung injury

Acute respiratory distress syndrome (ARDS) usually requires symptomatic supportive therapy by intubation and mechanical ventilation with the supplemental use of high oxygen concentrations. Although oxygen therapy represents a life-saving measure, the recent discovery of a critical tissue-protecting mechanism predicts that administration of oxygen to ARDS patients with uncontrolled pulmonary inflammation also may have dangerous side effects. Oxygenation may weaken the local tissue hypoxia-driven and adenosine A2A receptor (A2AR)-mediated anti-inflammatory mechanism and thereby further exacerbate lung injury. Here we report experiments with wild-type and adenosine A2AR-deficient mice that confirm the predicted effects of oxygen. These results also suggest the possibility of iatrogenic exacerbation of acute lung injury upon oxygen administration due to the oxygenation-associated elimination of A2AR-mediated lung tissue-protecting pathway. We show that this potential complication of clinically widely used oxygenation procedures could be completely prevented by intratracheal injection of a selective A2AR agonist to compensate for the oxygenation-related loss of the lung tissue-protecting endogenous adenosine. The identification of a major iatrogenic complication of oxygen therapy in conditions of acute lung inflammation attracts attention to the need for clinical and epidemiological studies of ARDS patients who require oxygen therapy. It is proposed that oxygen therapy in patients with ARDS and other causes of lung inflammation should be combined with anti-inflammatory measures, e.g., with inhalative application of A2AR agonists. The reported observations may also answer the long-standing question as to why the lungs are the most susceptible to inflammatory injury and why lung failure usually precedes multiple organ failure

Development of an Antioxidant Phytoextract of Lantana grisebachii with Lymphoprotective Activity against In Vitro Arsenic Toxicity

Phytochemicals have been presumed to possess prophylactic and curative properties in several pathologies, such as arsenic- (As-induced immunosuppression. Our aim was to discover a lymphoprotective extract from Lantana grisebachii Stuck. (Verbenaceae)(LG). We assessed its bioactivity and chemical composition using cell-based assays. Fractions produced from a hexane extract acutely induced nitrite formation in T- Activated cell cultures (P < 0.0001). Water extraction released a fraction lacking nitrite inducing activity in both lymphocyte types. Aqueous LG was found to be safe in proliferated and proliferating cells. The infusion-derived extract presented better antioxidant capacity in proportion to phenolic amount in lymphocytes (infusive LG- 1i at 100g/mL), which protected them against in vitro As-induced lymphotoxicity (P < 0.0001). This infusive LG phytoextract contained 10.23 ± 0.43mg/g of phenolics, with 58.46% being flavonoids. Among the phenolics, the only predominant compound was 0.723 mg of chlorogenic acid per gram of dry plant, in addition to 10 unknown minor compounds. A fatty acid profile was assessed. It contained one-third of saturated fatty acids, one-third of 9, followed by 6 (∼24%) and 3 (∼4%), and scarce 7. Summing up, L. grisebachiiwas a source of bioactive and lymphoprotective compounds, which could counteract As-toxicity. This supports its phytomedical use and research in order to reduce As-related dysfunctionsFil: Soria, Elio Andres. Universidad Nacional de Cordoba. Facultad de Medicina. Instituto de Biologia Celular; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Quiroga, Patricia L.. Universidad Nacional de Cordoba. Facultad de Medicina. Instituto de Biologia Celular; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Albrecht, Claudia. Universidad Nacional de Cordoba. Facultad de Medicina. Instituto de Biologia Celular; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Cordoba. Instituto de Investigaciones en Ciencias de la Salud; ArgentinaFil: Ramos Elizagaray, Sabina I.. Consejo Interuniversitario Nacional; ArgentinaFil: Cantero, Juan J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Río Cuarto. Facultad de Agronomía y Veterinaria; ArgentinaFil: Bongiovanni, Guillermina Azucena. Universidad Nacional del Comahue. Facultad de Ciencis Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación y Desarrollo en Ingeniería de Procesos, Biotecnología y Energías Alternativas; Argentin

AN EXPERIMENTAL SYSTEM FOR THE SIMULTANEOUS ESTIMATION OF MITOSTATIC AND LYMPHOTOXIC EFFECTS OF IMMUNOSUPPRESSANTS AND CYTOSTATICS

Sublethally (600 R) irradiated (CBA x C57BL)F1 mice were grafted intravenously with parental lymph node cells in doses ranging from 0.2 x 106 to 12 x 106. The transplantation of these lymphoid cells leads to inactivation of the recipient's endogenous CFU (as measured by the diminution of the number of colonies registered on the 10th day after irradiation). A 50% inactivation was observed when the graft size of the CBA cells was 0.52 x 106. This figure for C57BL cells was 10 times more. This experimental system evaluates two simultaneously developing processes: the multiplication of endogenous CFU and the homograft reaction of transplanted lymphocytes against them. Both processes can be quantitatively estimated simultaneously in the same experiment by the determination of the number of colonies in corresponding experimental groups. Thus it was possible in a single experiment to compare quantitatively the effect of immunosuppressants on two points: (a) mitostatic action (suppression of CFU) and (b) lymphotoxic action. The latter, a true immunosuppressive effect, represents suppression of GVH activity of lymphoid cells and is demonstrated by abolition of the inhibition of endogenous colony formation. In the present system we have tested 6-MP, ALS, cyclophosphamide, hydrocortisone, and other drugs. The definite mitostatic and lymphotoxic doses of drugs are ascertained. Cyclophosphamide and ALS proved to be drugs with high dose ranges of selective lymphotoxic action. Hydrocortisone acetate had a more narrow range of selective lymphotoxic effect. 6-MP and Imuran (azathioprine) failed to exert any selective action on lymphoid elements. They possessed pronounced mitostatic efficiency, however

Autophagy Blockage Up-Regulates HLA-Class-I Molecule Expression in Lung Cancer and Enhances Anti-PD-L1 Immunotherapy Efficacy

Simple Summary: The restoration of HLA-class-I expression in lung cancer cells may reverse immune evasion, enhance cytotoxic T-cell activity, and improve immune checkpoint inhibitors’ therapeutic efficacy. In the current study, we provide experimental evidence that autophagy blockage either at the late stage (chloroquine and bafilomycin) or early stage of the autophagic process (ULK1 inhibitors and MAP1LC3A silencing) can up-regulate the expression of HLA-class-I molecules in the A549 and H1299 NSCLC cell lines and their CD133+ stem cells. This upregulation enhances the cytotoxic activity of activated CD8+ T-cells, in particular after pre-incubation with anti-PD-L1 monoclonal antibodies. The restoration of HLA-class-I-mediated antigen presentation with autophagy blockers in lung cancer is a promising avenue that urgently requires further exploration in clinical trials. Abstract: Background/Objectives: Immune checkpoint inhibitors have an established role in non-small cell lung cancer (NSCLC) therapy. The loss of HLA-class-I expression allows cancer cell evasion from immune surveillance, disease progression, and failure of immunotherapy. The restoration of HLA-class-I expression may prove to be a game-changer in current immunotherapy strategies. Autophagic activity has been recently postulated to repress HLA-class-I expression in cancer cells. Methods: NSCLC cell lines (A549 and H1299) underwent late-stage (chloroquine and bafilomycin) and early-stage autophagy blockage (ULK1 inhibitors and MAP1LC3A silencing). The HLA-class-I expression was assessed with flow cytometry, a Western blot, and RT-PCR. NSCLC tissues were examined for MAP1LC3A and HLA-class-I expression using double immunohistochemistry. CD8+ T-cell cytotoxicity was examined in cancer cells pre-incubated with chloroquine and anti-PD-L1 monoclonal antibodies (Moabs); Results: A striking increase in HLA-class-I expression following incubation with chloroquine, bafilomycin, and IFNγ was noted in A549 and H1299 cancer cells, respectively. This effect was further confirmed in CD133+ cancer stem cells. HLA-class-I, β2-microglobulin, and TAP1 mRNA levels remained stable. Prolonged exposure to chloroquine further enhanced HLA-class-I expression. Similar results were noted following exposure to a ULK1 and a PIKfyve inhibitor. Permanent silencing of the MAP1LC3A gene resulted in enhanced HLA-class-I expression. In immunohistochemistry experiments, double LC3A+/HLA-class-I expression was seldom. Pre-incubation of H1299 cancer cells with chloroquine and anti-PD-L1 MoAbs increased the mean % of apoptotic/necrotic cells from 2.5% to 18.4%; Conclusions: Autophagy blockers acting either at late or early stages of the autophagic process may restore HLA-class-I-mediated antigen presentation, eventually leading to enhanced immunotherapy efficacy

Aktive Immuntherapie bei gastrointestinalen Tumoren: eine in vitro und in vivo Analyse

In der Habilitationsschrift wurden immuntherapeutische Konzepte bei gastrointestinalen Tumoren experimentell umgesetzt (Pankreaskarzinom, kolorektales Karzinom). Zunächst wurde die Effizienz der aktiv-unspezifischen Immuntherapie nach Applikation von mikrobiellen Mixen im ektopen Modell dargestellt. In einem spontanen Tumorgenesemodell konnte schließlich die immunologisch-vermittelte Wirksamkeit einer prophylaktischen und therapeutischen Vakzine erstmals präklinisch nachgewiesen werden. Beide gewählten Ansätze sind vielversprechend und sollten weiter präklinisch optimiert werden