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In our immune system the WBC plays the important role. WBC is also called as leucocytes or the White Blood Cells. Their role in the Blood stream is to destroy or attack the bacteria and parasites and other foreign body in the blood. These WBC circulate in the blood stream. There are different types of WBC. Total there are six types of WBC,


The Granulocytes and the agranulocytes are the two categories in which the WBC are divided

Following are the actions of WBC:

NEUTROPHILS: They are also knows as the Polymorphonuclear leukocytes or the PMN. It is most common type of WBC. In total WBC it accounts for about 65%. They act as the first line defense or the primary defenders against the infection caused by the bacteria of fungus.

The neutrophils are the first responders in destruction of foreign bodies, i.e., bacteria and fungi. Checking the PMN count does the diagnosis of the infection. These are the first WBC to increase in number during the infection. They are commonly seen during the inflammatory process and in the pus secretions. There are four signs of inflammation; Rubor (Redness), Dolor (Pain), Calor (Temperature), Tumor (Edema). The fifth sign added is the loss of function, called as the Functio-lasa.

BASOPHILS: The main function of the Basophils is to release the histamine, which is a chemical response to an infection. They are found in very less quantity in the total WBC count. It is present in total of 1% quantity in the total WBC count. The main function of the chemical Histamine is to initiate the inflammatory reaction after the infection.

EOSINOPHILS: The main function of the WBC is first defense against the parasites or for the parasitic infection. The Eosinophil’s also increase in the number during the asthma caused by the allergens, or during the allergic reactions. They are the last type of the granulocyte. They form total 4% of our leukocytes.

LYMPHOCYTES: This type of WBC lack in the membrane hence they are the agranulocytes. Lymphocytes are the first agranulocytes. The Lymphocytes accounts for 25% of total White Blood Cells. Lymphocytes are of three types; B cells, T cells, and the Natural killer cells.

All these have different functions.

The cells for the foreign bodies such as bacteria and the viruses make up the antibodies. The chemical or the antibodies produced by the cells are made to attack the specific chemical markers. These chemical markers are present outside the targeted foreign body. The reaction gets initiated when this antibody gets attached to the invading cell. By this reaction our body kills the foreign body. It may be bacteria or the virus.

There are two different types of T cells namely CD4 and CD8. One of it makes the immune defense against the foreign bodies (Virus or Bacteria), while the other actually goes and kills the target. The one, which makes the immune defense system, is the CD4 cell and one, which makes the kill, is the CD8 cell. In the diseases like HIV and AIDS this CD4 gets damaged, and allows the infection to increase.

MONOCYTES: The main function of the Monocytesis the Phagocytosis. The monocytes circulate in the blood stream and when the foreign bodies (bacteria and viruses) are found they engulf it and degrade it in to the smaller pieces. This process is called as the Phagocytosis. After the phagocytosis it is presented on the cell surface. By this presentation on the cell surface the T cell recognizes the make up of the foreign body and hence it becomes easy to kill many of such foreign cells.

There are total 6% Monocytes in the White Blood Cells. They live for much longer duration compared to other White Blood Cells.

MACROPHAGESThe function of the Macrophages is the same as that of the Monocytes. They too engulf the foreign bodies.

The Macrophages are the modified form of the Monocytes. There are some Monocytes, which circulate out side the blood stream in to the tissues of the body; such Monocytes are called as the Macrophages. Hence, they are similar to that of the Monocytes.

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The main function of white blood cells/WBCs is to fight against infection – bacterial, fungal etc. and foreign body. They act like the soldiers of the body.

There are different types of WBCs with different function.


  • Neutrophils – (most common) – chemotaxis, phagocytosis, killing.
  • Eosinophil – allergic inflammatory response.
  • Basophil – release of histamine in inflammatory response.


  • Lymphocytes – T lymphocytes-cellular immune reactions and immunoregulatory function.
  • B lymphocytes – engaged in synthesis of specific immunoglobulin antibodies.
  • Monocytes (macrophages) – phagocytosis.
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WBC acts same like a unicellular  amoeba. Like a amoeba WBC also engulf the bacteria  or any germs in our blood. This is the reason  why  we don't  get sick often. There times when germs are too much and we get sick.if there is  more amount of  WBC it is dangerous  Thank you .
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