Modulation of Structural and Functional Properties of Human Lymphocytes by Reactive Oxygen Species

Resumo

The effects of ROS on functional properties (cytotoxic activity, antibody-producing activity, TNFα synthesis, and free cytosol calcium level), membrane structure (by expression of some surface markers), and apoptosis of lymphocytic cells were estimated in the peripheral blood of healthy volunteers. ¹O₂, \( {\mathrm{O}}_2^{\underset{\_}{\bullet }} \), OH^•, and H₂O₂ mostly suppressed cytotoxic activity of lymphocytes against Ehrlich ascites carcinoma cells and inhibited IgG synthesis and expression of receptors and surface markers (Fc receptors, CD3, CD19, and CD56). The exposure of lymphocytes to H₂O₂ (10^—6 M), ¹O₂, and OH^• was followed by an increase in the level of a secondary messenger, intracellular calcium, in comparison with non-exposed cells. The presence of exogenous calcium in the medium for lymphocyte suspending induced an increase in the number of cells at early and late stages of apoptosis 6 h after exposure to H₂O₂ and ¹O₂ in comparison with lymphocytes incubated in Ca²⁺-free medium.