Malnutrition is a common cause of secondary immune deficiency and has been linked to an increased susceptibility to infection in humans. Malnutrition specifically affects T-cell-mediated immune responses. The aim of this study was to assess in lymphocytes from malnourished children the expression levels of IL-12, IL-18 and IL-21, molecules that induce the differentiation of T cells related to the immunological cellular response (Th1 response) and the production of cytokines related to the immunological cellular response (Th1 cytokines). We found that the expression levels of IL-12, IL-18 and IL-21 were significantly diminished in malnourished children compared to well-nourished children and were coincident with lower plasmatic levels of IL-2 and IFN-γ (Th1 cytokines). In this study, we show for the first time that the gene expression and intracellular production of cytokines responsible for Th1 cell differentiation (IL-12, IL-18 and IL-21) are diminished in malnourished children. As expected, this finding was related to lower plasmatic levels of IL-2 and IFN-γ. The decreased expression of Th1 cytokines observed in this study may contribute to the deterioration of the immunological Type 1 (cellular) response. We hypothesize that the decreased production of IL-12, IL-18 and IL-21 in malnourished children contributes to their inability to eradicate infections.

In conclusion, the results suggest that alterations in the balance of type 1/type 2 immune responses exist in malnourished children, and this could be the reason that the immunological system of the malnourished children is incapable of eradicating infections.

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A methodology which provides a high efficiency of giant vesicle formation was established using the gentle hydration method and a microplotter equipment. The method consists of preparing a mixture of zwitterionic egg yolk phosphatidylcholine/additive in solution and printing a number of droplets onto a glass substrate, which immediately dry after deposition. Then, gentle hydration of these micro-sized thin-films provides a high amount of giant liposomes, per microsized film. Several cases were studied by varying different compounds as additives (i.e., non-electrolytes and electrolytes) at different molar ratios, lipid to additive, in order to find the optimal conditions. Optical and confocal microscopies were employed to characterize vesicle formation. Studies indicate that the kosmotropic salt KH2PO4 at 1:10 molar concentration, EggPC to salt, is the most effective in vesicle production. Abundant liposome formation can be observed in a short time, about 5 min upon hydration. The osmotic pressure is the driven force to produce giant liposomes in our experiments, which is generated by dissolving the additive among two lipid lamellar phases in water. In salt experiments, the osmotic pressure strength is manly determined from the ion-specificity effect (i.e., the Hofmeister effect) rather than the concentration of the salt. The use of a salt as additive provides giant unilamellar vesicles (GUVs). The microplotter protocol provides benefits such as a facile, efficient and rapid way to prepare GUVs in mild conditions (i.e., free of solvents).