Explain the role of T-lymphocytes in cell mediated Immunity?

Explanation

The T-cells are responsible for the cell mediated immunity. In this type of immunity antibodies are not formed but the body produces large number of activated T-cells that are specially designed to destroy the foreign organisms.
1. When an antigen enters the body, T-cells get activated and individually respond to the antigen by producing their clones called lymphoblasts and memory cells.
2. These clones of T-cells are similar but perform different functions.
3. They do not produce antibodies but develop further to produce one of the following, 3 types of T-cells, namely. .
(a) T-killer cells : These destroy the antigen before it can spread an infection by secreting certain substances like cytolysin.
(b) T-helper cells : These activate B-cells (to produce antibodies) and T-Killer cells (To kill the antigens by secreting certain substances called lymphokines).
(c) T-suppressor cells : These inhibit the immune response of both T and B lymphocytes to foreign antigens, when infection is controlled.
4. The memory cells persist in the body and readily mount a secondary response against the pathogen if reinfection occurs.