Microparticle-mediated transfer of the viral receptors CAR and CD46, and the CFTR channel in a CHO cell model confers new functions to target cells

Cell microparticles (MPs) released in the extracellular milieu can embark plasma membrane and intracellular components which are specific of their cellular origin, and transfer them to target cells. The MP-mediated, cell-to-cell transfer of three human membrane glycoproteins of different degrees of complexity was investigated in the present study, using a CHO cell model system. We first tested the delivery of CAR and CD46, two monospanins which act as adenovirus receptors, to target CHO cells. CHO cells lack CAR and CD46, high affinity receptors for human adenovirus serotype 5 (HAdV5), and serotype 35 (HAdV35), respectively. We found that MPs derived from CHO cells (MP-donor cells) constitutively expressing CAR (MP-CAR) or CD46 (MP-CD46) were able to transfer CAR and CD46 to target CHO cells, and conferred selective permissiveness to HAdV5 and HAdV35. In addition, target CHO cells incubated with MP-CD46 acquired the CD46-associated function in complement regulation. We also explored the MP-mediated delivery of a dodecaspanin membrane glycoprotein, the CFTR to target CHO cells. CFTR functions as a chloride channel in human cells and is implicated in the genetic disease cystic fibrosis. Target CHO cells incubated with MPs produced by CHO cells constitutively expressing GFP-tagged CFTR (MP-GFP-CFTR) were found to gain a new cellular function, the chloride channel activity associated to CFTR. Time-course analysis of the appearance of GFP-CFTR in target cells suggested that MPs could achieve the delivery of CFTR to target cells via two mechanisms: the transfer of mature, membrane-inserted CFTR glycoprotein, and the transfer of CFTR-encoding mRNA. These results confirmed that cell-derived MPs represent a new class of promising therapeutic vehicles for the delivery of bioactive macromolecules, proteins or mRNAs, the latter exerting the desired therapeutic effect in target cells via de novo synthesis of their encoded proteins

Microparticles released by Listeria monocytogenes-infected macrophages are required for dendritic cell-elicited protective immunity

Interplay between macrophages and dendritic cells in the processing and presentation of bacterial antigens for T-cell immune responses remains poorly understood. Using a Listeria monocytogenes (Lm) infection model, we demonstrate that dendritic cells (DCs) require the support of macrophages to elicit protective immunity against Lm infection. DCs themselves were inefficient at taking up Lm but capable of taking up microparticles (MPs) released by Lm-infected macrophages. These MPs transferred Lm antigens to DCs, allowing DCs to present Lm antigen to effector T cells. MP-mediated Lm antigen transfer required MHC class I participation, since MHC class I deficiency in macrophages resulted in a significant reduction of T-cell activation. Moreover, the vaccination of mice with MPs from Lm-infected macrophages produced strong protective immunity against Lm infection. We here identify an intrinsic antigen transfer program between macrophages and DCs during Lm infection, and emphasize that macrophages also play an essential role in DC-elicited Lm-specific T-cell responses

Randomized study to evaluate the use of high-dose therapy as part of primary treatment for "aggressive" lymphoma

PURPOSE: This trial of the German High-Grade Non-Hodgkin's Lymphoma Study Group compares the use of high-dose therapy (HDT) as part of primary treatment with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) plus etoposide followed by involved-field (IF) radiotherapy in a randomized, multicenter, phase III study. PATIENTS AND METHODS: Three hundred twelve patients with "aggressive" non-Hodgkin's lymphoma aged <or= 60 years with elevated serum lactate dehydrogenase levels were included from 1990 to 1997. Patients with at least a minor response after two cycles of CHOEP (CHOP + etoposide 3 x 100 mg/m(2)) were to receive three further cycles of CHOEP followed by IF radiotherapy (arm A) or one further cycle of CHOEP followed by autologous stem-cell transplantation and IF radiotherapy (arm B). RESULTS: Among 158 patients randomized to arm B, 103 (65%) received HDT. The complete remission rate at the end of treatment was 62.9% in arm A and 69.9% in arm B. With a median observation time of 45.5 months, overall survival for all 312 patients was 63% after 3 years (63% for arm A, 62% for arm B; P =.68). Event-free survival was 49% for arm A versus 59% for arm B (P =.22). Relapse in arm B was associated with a significantly worse survival rate than relapse in arm A (P <.05). Relapse after HDT occurred early (median interval, 3 months). Six patients developed secondary neoplasia, three in arm A and three in arm B. CONCLUSION: Results of the randomized trial comparing CHOP-like chemotherapy with early HDT do not support the use of HDT with carmustine, etoposide, cytarabine, and melphalan following shortened standard chemotherapy

Agroecological management of cucurbit-infesting fruit fly: a review

Conventional crop protection with pesticides has limitations such as resistance of pests to pesticides and faunal imbalance. Agroecological crop protection is an attractive alternative based on the principles of agroecology. We present here this strategy using the case of Cucurbitaceae flies, which are the most important agricultural pests in Réunion. Research has been carried out on the bioecology of these insects and on the effectiveness of agroecological techniques. The main points are the following: the number of species of vegetable flies increased in the southern summer. Adult flies spend more than 90 % of their time on nonhost plants, with specific circadian rhythms. Several original agroecological techniques were designed, such as sanitation using augmentoria; trap plants, e.g., maize; adulticide bait; and the creation of habitats for predatory arthropods. Local growers are very satisfied with the results. They have reduced insecticide use with substantial cost savings and they have observed a decrease in losses and a lower phytosanitary workload. The education and training of students, professionals, and the general public has been a major aspect of this project. Increased knowledge of flies and agroecological management strategies of their populations can now be combined with modeling tools to facilitate the extension of the program to other areas or for educational purposes. Practices are currently being extended to other areas of the island and other countries of the Indian Ocean. This project is both a significant milestone for organic farming in Réunion and a precedent for other initiatives aimed at reducing or eliminating pesticides