Adhesion and proliferation of HeLa and fibroblast cells on chemically-modified gold surfaces.

The development of materials that allow proper functioning of cells on solid supports is directly relevant to the construction of living-cell biosensors. Both physical and chemical properties of the surfaces have been shown to be critical in this field. Our aim is to report correlations between chemical properties of surfaces and cell behavior by studying adhesion, viability and proliferation of fibroblasts and HeLa cells. Neither fibroblasts nor HeLa cells adhered to a hydrophobic surface. Fibroblasts were able to attach and proliferate well on all other surfaces tested. In contrast, on some surfaces where HeLa cells adhered and were viable, proliferation decreased by half while on others proliferation was not affected. Proliferation was significantly correlated with the level of adsorption of serum proteins on the surface (quantified by surface plasmon resonance), but not with surface wettability (water contact angle). Interestingly, surfaces modified with COOH and HSO3 groups were the ones that favored most protein adsorption and allowed the best measures for HeLa cell proliferation. The decrease of HeLa cell proliferation on surfaces covered with poly-L-lysine (PL) was related with the profile of integrin expression. Compared to a polystyrene control surface, there was an increase in αV and αVß3 and a decrease in α2 and α3, indicating that migration rather than proliferation could be favored on PL functionalized surfaces. These results indicate that charge is more important than wettability to determine biocompatibility.

Immunomodulation of liver injury by Ascaris suum extract in an experimental model of autoimmune hepatitis.

Adult worm extract from Ascaris suum (Asc) has immunosuppressive activity and elicits Th2/IL-4/IL-10 response. This study evaluated the prophylactic and therapeutic effect of Asc in a murine model of concanavalin A (ConA)-induced autoimmune hepatitis (AIH). BALB/c mice received ConA, iv, (20 mg/kg), and three groups of animals were formed: (1) AIH, received only ConA; (2) AIH + Asc prophylactic, treated with Asc (1 mg/ml), ip, 30 min before of the AIH; and (3) AIH + Asc therapeutic, treated with Asc 2 h after the AIH. Plasma transaminase and immunoglobulins (measured at 8 and 24 h and 7 days after treatment) and cytokine production (IL-4, IL-10, IL-13, and IFN-γ) by splenocytes upon ConA and Asc stimulus were compared. The livers were weighed and examined histologically. In the AIH group, there was an increase in liver weight, transaminase levels, and total immunoglobulins. These parameters were reduced by 8-24 h and 7 days in the prophylactic group, but in the therapeutic group, only on day 7. The survival rate of mice in the AIH group was 38.5%, compared to 67% in the therapeutic Asc group. The survival rate of the animals with AIH that were prophylactically treated with Asc was 100%. A decrease of cellular infiltration and high levels of IL-4, IL-10, and IL-13 were induced by Asc. An increase of liver fibrosis was also observed, but with less intensity with prophylactic treatment. Thus, the Ascaris components have an inhibitory effect on AIH, with an intense Th2 immune response.