title: [Intracellular events in T lymphocyte's activation].
abstract: Adaptive immune responses are not initiated at the site where a pathogen first establishes a focus of infection. They occur in the organized peripheral lymphoid tissues, to which the pathogen or its products are transported, trapped, captured by specialized cells, called antigen-presenting cells (APC), which process and present the antigen to T lymphocytes. Activation of naive T cells requires two signals: the first signal is represented by the specific recognition of a foreign peptide fragment bound to a self MHC molecule, but this is not enough. The second signal, called co-stimulatory signal is represented by other molecules, expressed on the membrane or secreted by the APCs for which T cells express specific ligands. Binding of antigen to the T-cell receptor initiates a series of biochemical changes within the T cell, involving a large number of molecules.
authors.affiliation: Facultatea de Medicină Stomatologică, Universitatea de Medicină şi Farmacie Gr.T. Popa Iaşi.
authors.forename: Corina
authors.initials: C
authors.lastname: Cianga
authors.forename: P
authors.initials: P
authors.lastname: Cianga
mesh_terms: D000938:Antigen-Presenting Cells / Q000276:immunology / Q000502:physiology*; D006801:Humans; D007111:Immunity, Cellular; D008213:Lymphocyte Activation; D008285:Major Histocompatibility Complex / Q000276:immunology; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology*
chemical_list: D011948:Receptors, Antigen, T-Cell