Question

T-cells in lymph nodes

• A. occur predominantly in the medullary region
• B. are only of the cytotoxic type
• C. are phagocytic
• D. are absent in Di George syndrome

Answer 1

The correct option is D are absent in Di George syndrome

T cells are so called because they are predominantly produced in the medullary region of thymus. They recognise foreign particles (antigen) by a surface expressed, highly variable, T cell receptor (TCR). There are two major types of T cells: the helper T cell and the cytotoxic T cell. As the names suggest helper T cells ‘help’ other cells of the immune system, whilst cytotoxic T cells kill virally infected cells and tumours. T cells with CD4 molecules bind peptides displayed on MHC II molecules. As discussed earlier, such peptides are derived from phagocytized sources, and thus these T cells interact with only with certain special, phagocytic cells.

So, the correct options are 'Option D'.