T cell


    In Context

    • The study reveals the durability and robustness of the T cell responses against variants, including Delta, even after one year of infection. 
      • Strong and long standing T cell responses were seen even when people were not reinfected or vaccinated

    About T cell

    • T cells are a diverse and important group of lymphocytes that mature and undergo positive and negative selection processes in the thymus. 
    • Types: 
      • There are several types of T cells; the most common and well-known are the CD4+ T cells (helper T cells) and CD8+ T Cells (cytotoxic T cells, or killer T cells).
      • As the names suggest, helper T cells ‘help’ other cells of the immune system, whilst cytotoxic T cells kill virally infected cells and tumours.
    • Functions:
      • T cells play a vital role in both components of active immunity, including cell-mediated and to some extent humoral immunity. 
      •  T cells cannot recognize soluble, free antigens. T cells can only recognize protein-based, receptor-bound antigens.