Host directed immunomodulation represents potential new adjuvant therapies in infectious diseases such as tuberculosis. Major cytokines like TNFα exert a multifold role in host control of mycobacterial infections. GM-CSF and its receptor are over-expressed during acute M. tuberculosis infection and we asked how GM-CSF neutralization might affect host response, both in immunocompetent and in immunocompromised TNFα-deficient mice. GM-CSF neutralizing antibodies, at a dose effectively preventing acute lung inflammation, did not affect M. tuberculosis bacterial burden, but increased the number of granuloma in wild-type mice. We next assessed whether GM-CSF neutralization might affect the control of M. tuberculosis by isoniazid/rifampicin chemotherapy. GM-CSF neutralization compromised the bacterial control under sub-optimal isoniazid/rifampicin treatment in TNFα-deficient mice, leading to exacerbated lung inflammation with necrotic granulomatous structures and high numbers of intracellular M. tuberculosis bacilli. In vitro, GM-CSF neutralization promoted M2 anti-inflammatory phenotype in M. bovis BCG infected macrophages, with reduced mycobactericidal NO production and higher intracellular M. bovis BCG burden. Thus, GM-CSF pathway overexpression during acute M. tuberculosis infection contributes to an efficient M1 response, and interfering with GM-CSF pathway in the course of infection may impair the host inflammatory response against M. tuberculosis.

Coral reef assemblages generally form gradients of spatial structures which are governed by a variety of interacting physical and biological processes that vary in intensity, frequency, and spatial scale. Assessing the structure of contemporary reef assemblages may help to understand future changes and to identify appropriate conservation actions. The spatial distribution and interannual variability (from 2006 to 2008) of coral assemblages were investigated at 10 stations in the southwestern lagoon of New Caledonia, and the strength of the cross-shelf gradient was evaluated. Coral cover, generic richness, and abundance of adult and juvenile assemblages were highly variable within and among the three major reef habitats (fringing, mid-shelf, and barrier reefs). Abundance increased with distance from shore, whereas generic richness and cover were not correlated with shelf position. Assemblage composition was generally related to habitat, even though some mid-shelf and fringing reef assemblages resembled those observed on other habitats. A significant correlation between juvenile and adult distributions was recorded, suggesting that adult assemblages are partly controlled by the short-term history of recruitment patterns. The interannual variation of coral assemblages was far less pronounced, with significant changes only detected at some mid-shelf and barrier reefs, for a few genera characterised by high turn-over.

International audienceAn index CCO (cover, characteristic species, opportunistic species) has been developed for the implementation of the European Water Framework Directory (WFD) in coastal waters, using intertidal macroalgal communities as bio-indicator (Biological Quality Element). CCO is based on the calculation of three metrics corresponding to the global cover of macroalgal communities (metric 1), the number of characteristic species per topographic level/seaweed community (metric 2) and the cover of opportunistic species (metric 3). The final rating is obtained by pooling the scores of the three metrics. Results are given for 32 sites in 29 water bodies, grouped into four biogeographic regions along the Channel–Atlantic coasts of France. Over the six-year study, most of sites were sampled twice each (every three years). CCO index revealed that 25 coastal water bodies of both the Channel and the Bay of Biscay were in good or high ecological quality status (EQS), whereas only 4 of them were moderate and none in poor to bad status. However, significant differences have been found between sites and between geographic regions, water bodies located in Brittany obtaining the best EQS. No significant change occurred between the three-year sampling sets. A significant correlation has been established between a three-component anthropogenic pressure index and CCO ratings, showing the accuracy of CCO to evaluate the impact of anthropic activities on the structure and development of macroalgal communities as indicator of the ecological quality of coastal water bodies

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