QS Study

Lymphocyte is an agranular type of white blood cell takes part in immunity. It is a form of small leucocyte (white blood cell) with a single round nucleus, occurring especially in the lymphatic system. They are made in the bone marrow and found in the blood and lymph tissue.


(i) No granules present.

(ii) More cytoplasm.

(iii) Cell size: 8 to 16 μm

(iv) Nucleus: Rounded

(v) Stain: Nucleus → Red; Cytoplasm → Blue

Lymphocyte covers 20-40% of total circulation cell in blood and lymphatic tissue.

Fig: Lymphocyte in white blood cell


(a) According to size: Small Lymphocyte and Large Lymphocyte.

(b) According to function: B-Lymphocyte and T-Tymphocyte (Helper T cell, Cytoxic T cell, and Suppressor T cell).

Cytotoxic T cells, destroy cells in our body that have been infected with an antigen, cancer cells, and foreign cells like transplanted organs. Helper T cells direct the immune response of B cells and other T cells.


(i) Give body both humoral and cell-mediated immunity.

(ii) N.K cell kills foreign particles.

(iii) Helps in the repair of tissue.

(iv) Cytotoxic T-cell destroys cancer cell, heart transplant cells.

(v) It is responsible for cell-mediated immunity.

(vi) Directly attacking foreign substances such as bacteria, viruses, or strange tissues;

(vii) Responsible for rejection of transplanted tissue.