During the last several years, the important progress has been achieved in studying activation and proliferation processes altogether with differentiation of mononuclear cells and regulatory course of immune response. In addition to molecular biology, also the biochemical characterization of interleukins, mainly Interleukin 2 (IL 2), is of a substantial import. IL 2 is actionning as an amplificator of T and B immune cellular reactions, and it influences the production of lymphokines, i.e., gamma interferon as well as participates in antitumorous immunity. IL 2 belongs to the range of products being secreted by T lymphocytes following the specific antigenic or polyclonal mitogenic simulation of cells. It can be classed as a growth factor of cells and regulatory factor of immune responsiveness. The human IL 2 was isolated as a protein with Mr 16 kD. On the basis of complementary DNA, the molecular weight has been determined for IL 2 as 15.4 kD. The IL 2-related human gen is localized on 4th chromosome and the product of the respective gen is a protein composed of 133 amino acids. This very protein undergoes glycosylation on the 3d position having alpha-helicoid conformation. The murine IL 2 occurs rather as a dimer composed of two protein chains with Mr 16-18 kD. Variable degrees of glycosylation involve the heterogeneity and pI differences in isolated forms of IL 2. Actions of IL2 are triggered by its interaction with specific receptor, which appears on the T cells no sooner as they are activated by the antigen or mitogen. Following the IL 2 with receptor interaction, the hydrolysis of phosphatidylinositolphosphate occurs intracellularly as well as activation of proteinkinase C and a track of other biochemical reactions non-elucidated till now, which lead up to the transcription regulation of genes and transfer of mitotic apparatus from G1 into S phase of cellular cycle and of division of cells.

Ustav lékarské biochemie 2 katedry interních oborů farmakologie a lékarské biochemie