Immunosuppressive Activity of Abatacept on Circulating T Helper Lymphocytes from Juvenile Idiopathic Arthritis Patients

BACKGROUND: Abatacept is used in the treatment of juvenile idiopathic arthritis (JIA) patients, but the activity of the drug on T helper cell function is not yet fully known. METHODS: The ability of abatacept to affect cytokine production in vitro and the proliferative response to both recall antigens and polyclonal stimulation was firstly assessed in healthy donors. Then, 10 JIA patients who were due to start abatacept treatment were recruited and longitudinally evaluated during the first 90 days of therapy. Both their clinical response to the treatment and in vitro analysis aimed to assess the proliferative response to recall antigens and the proportions of circulating T helper subsets. RESULTS: Abatacept reduced the proliferative response to recall antigens and the production of proinflammatory cytokines such as IFN-\u3b3 and TNF-\u3b1 in healthy donors in vitro. It was also efficient in improving symptoms and reducing parameters of inflammation in JIA patients. Abatacept reduced the proliferative response to recall antigens, and this effect was significant soon after drug infusion (2 days). Regarding the proportions of circulating CD4+ T lymphocytes, only a reduction in the frequencies of circulating Treg cells was observed. CONCLUSIONS: Abatacept in vitro inhibits proliferation and cytokine production in healthy donors, and reduces parameters of inflammation in vivo in JIA patients. The reduction of the proliferative response to recall antigens induced by abatacept was evident only soon after drug administration, suggesting that its immunosuppressive activity is maintained only for a short time

Eomes controls the development of Th17-derived (non-classic) Th1 cells during chronic inflammation

It is well accepted that Th17 cells are a highly plastic cell subset that can be easily directed towards the Th1 phenotype in vitro and also in vivo during inflammation. However, there is an ongoing debate regarding the reverse plasticity (conversion from Th1 to Th17). We show here that ectopic ROR-\u3b3t expression can restore or initiate IL-17 expression by non-classic or classic Th1 cells, respectively, while common pro-Th17 cytokine cocktails are ineffective. This stability of the Th1 phenotype is at least partially due to the presence of a molecular machinery governed by the transcription factor Eomes, which promotes IFN-\u3b3 secretion while inhibiting the expression of ROR-\u3b3t and IL-17. By using a mouse model of T cell-dependent colitis we demonstrate that Eomes controls non-classic Th1 cell development also in vivo and promotes their pathogenic potential. Eomes expression associates to a highly inflammatory phenotype also in patients with juvenile idiopathic arthritis. Indeed, it favors the acquisition of a cytotoxic signature, and promotes the development of IFN-\u3b3+ GM-CSF+ cells that have been described to be pathogenic in chronic inflammatory disorders

Isolation of a euryhaline microalgal strain, Tetraselmis sp CTP4, as a robust feedstock for biodiesel production

Bioprospecting for novel microalgal strains is key to improving the feasibility of microalgae-derived biodiesel production. Tetraselmis sp. CTP4 (Chlorophyta, Chlorodendrophyceae) was isolated using fluorescence activated cell sorting (FACS) in order to screen novel lipid-rich microalgae. CTP4 is a robust, euryhaline strain able to grow in seawater growth medium as well as in non-sterile urban wastewater. Because of its large cell size (9-22 mu m), CTP4 settles down after a six-hour sedimentation step. This leads to a medium removal efficiency of 80%, allowing a significant decrease of biomass dewatering costs. Using a two-stage system, a 3-fold increase in lipid content (up to 33% of DW) and a 2-fold enhancement in lipid productivity (up to 52.1 mg L-1 d(-1)) were observed upon exposure to nutrient depletion for 7 days. The biodiesel synthesized from the lipids of CTP4 contained high levels of oleic acid (25.67% of total fatty acids content) and minor amounts of polyunsaturated fatty acids with >= 4 double bonds (< 1%). As a result, this biofuel complies with most of the European (EN14214) and American (ASTM D6751) specifications, which commonly used microalgal feedstocks are usually unable to meet. In conclusion, Tetraselmis sp. CTP4 displays promising features as feedstock with lower downstream processing costs for biomass dewatering and biodiesel refining