Question

Cells responsible for cell–mediated response are

• A.
  T–cytotoxic cells
• B.
  T–helper cells
• C.
  B–cells
• D.
  All of these

Answer 1

The correct option is A

T–cytotoxic cells
T-lymphocytes, highly specialised cells are responsible for cell-mediated immune response. These cells attack directly on pathogens at the site of infection. These cells are morphologically similar but functionally are of four types;
(i) T-helper cells
(ii) T-killer or cytotoxic cells
(iii) T-suppressor cell
(iv) T memory cells.

Killer T cells (cytotoxic T cells) assist with the elimination of infected body cells by releasing toxins into them and promoting apoptosis. Helper T cells act to activate other immune cells.

B cells are at the centre of the adaptive humoral immune system and are responsible for mediating the production of antigen-specific immunoglobulin (Ig) directed against invasive pathogens (typically known as antibodies).

So the correct answer is "T-cytotoxic cells".