TZellReaktion

TZellReaktion is a term used in immunology to describe the adaptive immune response mediated by T lymphocytes. In German-language and some English texts, it refers to the T-cell–driven phase of immunity that follows antigen exposure and involves recognition, activation, and effector functions of T cells.

The process begins when professional antigen-presenting cells present peptide–MHC complexes to naive T cells. Co-stimulatory signals, such as CD28 binding to B7, are required to fully activate T cells and prevent anergy. The cytokine milieu then guides differentiation into CD4+ helper T cells and CD8+ cytotoxic T cells, with regulatory T cells potentially modulating the response. Helper T cells coordinate the broader immune reaction, supporting B cell antibody production and macrophage activation, while cytotoxic T cells directly target and destroy infected or malignant cells.

Key features of a TZellReaktion include clonal expansion of antigen-specific T cells, differentiation into effector and memory subsets, and the secretion of cytokines that shape the local and systemic response. The reaction is tightly regulated and usually concludes with contraction and the formation of memory T cells; chronic stimulation can lead to T-cell exhaustion or autoimmunity in susceptible contexts.

Clinical relevance is significant: vaccines aim to elicit robust TZellReaktion, and many cancer immunotherapies seek to enhance T-cell responses. Measurements of the TZellReaktion in research and clinical settings include flow cytometry, intracellular cytokine staining, ELISPOT assays, and MHC-tetramer labeling to quantify antigen-specific T cells.

Note: TZellReaktion is not a universally standardized term and may be used in varying contexts to denote the T-cell component of the immune response.