Infection of implanted materials by bacteria constitutes one of the most serious complications following prosthetic surgery. In the present study, we developed a new strategy based on the insertion of an antimicrobial peptide (defensin from Anopheles gambiae mosquitoes) into polyelectrolyte multilayer films built by the alternate deposition of polyanions and polycations. Quartz crystal microbalance and streaming potential measurements were used to follow step by step the construction of the multilayer films and embedding of the defensin within the films. Antimicrobial assays were performed with two strains: Micrococcus luteus (a gram-positive bacterium) and Escherichia coli D22 (a gram-negative bacterium). The inhibition of E. coli D22 growth at the surface of defensin-functionalized films was found to be 98% when 10 antimicrobial peptide layers were inserted in the film architecture. Noticeably, the biofunctionalization could be achieved only when positively charged poly(L-lysine) was the outermost layer of the film. On the basis of the results of bacterial adhesion experiments observed by confocal or electron microscopy, these observations could result from the close interaction of the bacteria with the positively charged ends of the films, which allows defensin to interact with the bacterial membrane structure. These results open new possibilities for the use of such easily built and functionalized architectures onto any type of implantable biomaterial. The modified surfaces are active against microbial infection and represent a novel means of local host protection.

Drosophila is a powerful model system to study the regulatory and effector mechanisms of innate immunity. To identify molecules induced in the course of viral infection in this insect, we have developed a model based on intrathoracic injection of the picorna-like Drosophila C virus (DCV). We have used MALDI-TOF mass spectrometry to compare the hemolymph of DCV infected flies and control flies. By contrast with the strong humoral response triggered by injection of bacteria or fungal spores, we have identified only one molecule induced in the hemolymph of virus infected flies. This molecule, pherokine-2 (Phk-2), is related to OS-D/ A10 (Phk-1), which was previously characterized as a putative odor/pheromone binding protein specifically expressed in antennae. The virus-induced molecule is also similar to the product of the gene CG9358 (Phk-3), which is induced by septic injury. Both Phk-2 and Phk-3 are strongly expressed during metamorphosis, suggesting that they may participate in tissue-remodeling.

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FETO is feasible in the non-human primate, which closely reflects procedures in humans. The non-human primate model for FETO, specially the rhesus monkeys, may be useful for future studies concerning the mechanisms related to the lung growth after transitory fetal tracheal occlusion.