T-2 toxin inhibits the differentiation of human monocytes into dendritic cells and macrophages.

The aim of this work was to study the in vitro effect of T-2 toxin on human monocyte differentiation into macrophages and dendritic cells. Cytotoxicity of T-2 toxin on monocytes, on monocytes in differentiation process into macrophages or dendritic cells, and on immature dendritic cells and macrophages was evaluated to determine IC50. Monocytes are more sensitive to T-2 toxin than to differentiate cells. IC50 were equal to 0.11 nM for monocyte, to 45 and 30 nM for monocyte during differentiation process for 24 and 48 h of incubation, respectively, to 38 and 20 nM for immature dendritic cells after 24 and 48 h of incubation, and to 22 and 20 nM for macrophages after 24 and 48 h of incubation. T-2 toxin effects on monocyte differentiation process into macrophages have been explored: according to phenotypic expressions (CD71, CD14, CD11a, CD80, CD86, HLA-DR and CD64), endocytic capacity, phagocytosis, burst respiratory activity and TNF-alpha secretion. In the presence of 10 nM of T-2 toxin (no cytotoxic concentration), CD71 expression is downregulated compared to control. Endocytosis and phagocytosis capacities are less effective as burst respiratory activity and TNF-alpha secretion. Monocyte differentiation process into dendritic cells in the presence of 10 nM T-2 toxin is also markedly disturbed. Expression of CD1a (specific dendritic cells marker) is downregulated while that of CD14 (specific monocyte marker) is upregulated. CD11a, CD80, CD86, HLA-DR and CD64 expressions did not change. These results show that T-2 toxin disturbs human monocytes differentiation process into macrophages and dendritic cells. These results could significantly contribute to immunosuppressive properties of this alimentary toxin.

Evaluation of shellfish consumption in Nha Trang City, Southern coastal Vietnam.

INTRODUCTION: Shellfish consumption may be a significant pathway to food contaminants such as heavy metals, pesticides and phycotoxins. Currently, little information exists about consumption of shellfish in Vietnam. Such data could be of interest in terms of nutritional value or risk assessment. METHODS: Consumption of shellfish was assessed using a food frequency questionnaire and validated by a 7-day recall method. Approximately 1% of the city population of Nha Trang was selected yielding a final sample of 440 participants. The participants were above 18 years of age, in apparently good health and were shellfish consumers. RESULTS: In South coastal Vietnam, the types of shellfish most consumed are green mussel, squid, crab and shrimp. The mean consumption rates of the bivalves, crustaceans, gastropods, cephalopods, echinoderms and all shellfish combined were 39.3, 20.9, 16.4, 11.2, 0.3 and 88.1 g/person/day, respectively. The consumption rate was slightly higher in the age group of 30-54 years, than in the younger (18-29 years) and older (55 years and above) age groups. Shellfish is essentially purchased in the markets and temporary markets, and mostly consumed during the dry season. CONCLUSION: Shellfish consumption in the Southern coastal region of Vietnam is high compared to consumption levels in other countries; it is also high compared to consumption levels of Vietnamese emigrants. Such data may be useful for further investigation on nutrition perspectives and in term of risk assessment of shellfish contaminants.