Types and Function of White Blood Cells (WBCs) (2023)

White blood cells (WBCs) are a part of the immune system. They help fight infection and defend the body against other foreign materials.

Different types of white blood cells have different jobs. Some are involved in recognizing intruders. Some kill harmful bacteria. Others make antibodies to protect your body against exposure to bacteria and viruses.

This article discusses the different types of white blood cells and their various functions.

Types of WBC

White blood cells are are also known as leukocytes. They are the body's defense against infections. There are several different types with different purposes.

Some of the cells are part of our innate immune system, meaning they know from birth to attack foreigners. Others are part of our humoral or learned immune system. Humoral immune cells manufacture antibodies after exposure to a germ. This way, the body can be prepared for another attack by that germ.


Neutrophils make up roughly half of the white blood cell population. They are usually the first cells of the immune system to respond to invaders such as bacteria or viruses.

As first responders, they also send out signals alerting other cells in the immune system to come to the scene.

Neutrophils are the main cells found in pus. Once released from the bone marrow, these cells live for only around eight hours. Your body produces roughly 100 billion of these cells every day.


Eosinophils also play a role in fighting off bacteria. They are very important in responding to parasitic infections (such as worms) as well.

They are perhaps best known for their role in triggering allergy symptoms. Eosinophils can go overboard in mounting an immune response against something harmless. For example, eosinophils mistake pollen for a foreign invader.

Eosinophils account for no more than 5% of the white blood cells in your bloodstream. However, there are high concentrations of eosinophils in the digestive tract.


Basophils account for only around 1% of white blood cells. These cells are perhaps best known for their role in asthma. However, they are important in mounting a non-specific immune response to pathogens, organisms that can cause disease.

When stimulated, these cells release histamine, among other chemicals. This can result in inflammation and narrowing of the airways.

Lymphocytes(B and T)

Lymphocytes are also essential in the immune system. They come in two forms: B cells and T cells. Unlike other white blood cells that provide non-specific immunity, B and T cells have specific purposes.

B lymphocytes (B cells) are responsible for humoral immunity, which is the immune response that involves antibodies. B cells produce the antibodies that "remember" an infection. They stand ready in case your body is exposed to that pathogen again.

T cells recognize specific foreign invaders and are responsible for directly killing them. "Memory" T cells also remember an invader after an infection and respond quickly if it is seen again.

B lymphocytes play a key role in the effectiveness of many current vaccines. In some cases, such as tuberculosis and pertussis vaccines, T lymphocytes are the main players.


Monocytes are the garbage trucks of the immune system. Around 5% to 12% of white blood cells in your bloodstream are monocytes. Their most important function is to clean up dead cells in the body.


Leukocytes, better known as white blood cells, take on different forms that perform different roles in the immune system. These include:

(Video) Video 9 White Blood Cells Types and Functions

  • Neutrophils are the first responder of immune cells.
  • Basophils release histamine to mount a non-specific immune response.
  • Eosinophils fight bacteria and parasites but also provoke allergy symptoms.
  • Lymphocytes are B and T cells that defend against specific invaders.
  • Monocytes clean up dead cells.

How WBCs Are Formed

White blood cells begin in the bone marrow in a process called hematopoiesis. All blood cells descend from a common hematopoietic stem cell (HSC). This is also called a "pluripotent" stem cell. These stem cells differentiate—or specialize—in different stages.

The HSC cell first separates into either a lymphoid or myeloid stem cell.

The lymphoid stem cell gives rise to the lymphoid cell line. This is the family of cells that produces B cells and T cells.

The myeloid stem cells give rise to cells called myeloblasts. These further evolve into macrophages, monocytes, neutrophils, basophils, and eosinophils. Myeloblasts can also turn into red blood cells and platelets.

Elevated White Blood Cell Counts

Infections usually cause an elevated white blood cell count, but there are also other possible causes. WBC counts can be increased by overproduction. In other words, the body may release white blood cells early from the bone marrow.

Stress of any form can result in this release of white blood cells. Some causes of an increased white blood cell count include:

  • Infections
  • Cancers such as leukemias, lymphomas, and myelomas, in which a greater number of white blood cells are manufactured
  • Inflammation, such as inflammatory bowel disease and autoimmune disorders
  • Trauma, ranging from fractures to emotional stress
  • Pregnancy
  • Asthma and allergies
  • Exercise

In severe infections, immature white blood cells called blasts may be present. Blasts often appear when the body attempts to get white blood cells on the scene quickly.

Low White Blood Cell Counts

Conditions that may result in a low white blood cellcount include:

  • Severe infections
  • Bone marrow damage or disorders including aplastic anemia, bone marrow "takeover" by blood cancers or metastatic cancer, or drug or chemical-related damage to the bone marrow
  • Autoimmune diseases such as lupus
  • Splenic "sequestration," where white blood cells are accumulated in the spleen.


On its own, a low WBC count doesn't have symptoms. But a low count will often lead to an infection, because not enough white cells are present to fight off the invader. Symptoms of infection may include:

  • Fever
  • Cough
  • Painful or frequent urination
  • Blood in the stools
  • Diarrhea
  • Redness, swelling, or warmth in a region of infection


One of chemotherapy's most common and dangerous side effects is its effect on white blood cells known as neutrophils. Recall that neutrophils are the first responders of our immune system.

A decrease in neutrophils during chemotherapy, known as chemotherapy-inducedneutropenia, increases the risk of serious infection.

Neutropenia makes it more difficult for the body to fight off infections. As a result, bacteria that are normally not very harmful can cause serious illness.


White blood cells are an important part of our immune system. Different types of white blood cells perform different functions in the body. Overall, white blood cells help to protect us against bacteria, viruses, and parasites.

A high white blood cell count is usually a sign of an infection or illness. A low white blood cell count can indicate another type of problem. Low white blood cell counts can leave you vulnerable to serious infections. Chemotherapy is a common cause of low white blood cell counts.

Frequently Asked Questions

  • What is the normal range of white blood cells?

    The normal range (total) of white blood cells is between 4,000 and 10,000 cells per microliter (mcL).

    (Video) White Blood Cells (WBCs) | Your body’s Defense | Hematology

  • What causes a high number of lymphocytes?

    A high number of lymphocytes (lymphocytosis) can be caused by the body's immune system fighting against infection. In these cases, the elevated number of lymphocytes is temporary. However, lymphocytosis can also be caused by several underlying medical conditions, including leukemia.

  • How many types of white blood cells are there?

    There are five types of white blood cells (leukocytes):

    • Neutrophils
    • Lymphocytes (B and T)
    • Monocytes
    • Basophils
    • Eosinophils
  • What does a high WBC mean?

    A high white blood count (WBC) can be a symptom of an underlying disorder. Disorders that are related to a high WBC include autoimmune or inflammatory disease, bacterial or viral infection, leukemia, Hodgkin's disease, or allergic reaction.

  • What are the symptoms of eosinophilia?

    Eosinophilia symptoms can include fever, night sweats, fatigue, and weight loss. This condition is caused by the body producing an excessive number of eosinophils, a type of leukocyte (white blood cell).

  • Where are white blood cells made?

    White blood cells are made in the bone marrow.

13 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

  1. Mayadas TN, Cullere X, Lowell CA. The multifaceted functions of neutrophils. Annu Rev Pathol. 2014;9:181-218. doi:10.1146/annurev-pathol-020712-164023

  2. Mcbrien CN, Menzies-Gow A. The biology of eosinophils and their role in asthma. Front Med (Lausanne). 2017;4:93. doi:10.3389/fmed.2017.00093

  3. Cromheecke JL, Nguyen KT, Huston DP. Emerging role of human basophil biology in health and disease. Curr Allergy Asthma Rep. 2014;14(1):408. doi:10.1007/s11882-013-0408-2

  4. Hoffman W, Lakkis FG, Chalasani G. B cells, antibodies, and more. Clin J Am Soc Nephrol. 2016;11(1):137-54. doi:10.2215/CJN.09430915

  5. Karlmark KR, Tacke F, Dunay IR. Monocytes in health and disease - Minireview. Eur J Microbiol Immunol (Bp). 2012;2(2):97-102. doi:10.1556/EuJMI.2.2012.2.1

  6. Görgens A, Radtke S, Horn PA, Giebel B. New relationships of human hematopoietic lineages facilitate detection of multipotent hematopoietic stem and progenitor cells.Cell Cycle. 2013;12(22):3478-82. doi:10.4161/cc.26900

  7. Hong JW, Noh JH, Kim DJ. Association between White Blood Cell Counts within Normal Range and Hemoglobin A1c in a Korean Population. Endocrinol Metab (Seoul). 2018;33(1):79-87. doi:10.3803/EnM.2018.33.1.79

  8. Riley LK, Rupert J. Evaluation of patients with leukocytosis. Am Fam Physician. 2015;92(11):1004-11.

  9. Flores-Mireles AL, Walker JN, Caparon M, Hultgren SJ. Urinary tract infections: epidemiology, mechanisms of infection and treatment options. Nat Rev Microbiol. 2015;13(5):269-84. doi:10.1038/nrmicro3432

  10. Kasi PM, Grothey A. Chemotherapy-induced neutropenia as a prognostic and predictive marker of outcomes in solid-tumor patients. Drugs. 2018;78(7):737-745. doi:10.1007/s40265-018-0909-3

  11. Cleveland Clinic. Lymphocytosis.

  12. MedlinePlus. White blood count (WBC).

  13. Kanuru S, Sapra A. Eosinophilia. StatPearls.

Additional Reading

(Video) Functions of WBCs ( White Blood Cells )

Types and Function of White Blood Cells (WBCs) (1)

By Lynne Eldridge, MD
Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."

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(Video) Types of White Blood Cells (Leukocytes)
(Video) Structure and Function of White Blood Cells - Leukocytes - Leucocytes


What are the types of Wbcs and their function? ›

Neutrophils are the first responder of immune cells. Basophils release histamine to mount a non-specific immune response. Eosinophils fight bacteria and parasites but also provoke allergy symptoms. Lymphocytes are B and T cells that defend against specific invaders.

What is the main function of the WBC? ›

White blood cells, also known as leukocytes, are responsible for protecting your body from infection. As part of your immune system, white blood cells circulate in your blood and respond to injury or illness.

What are the four functions of WBC? ›

White blood cells are also referred to as leukocytes and form a major part of the immune system. The granulocytes respond to allergic reactions and take part in providing the general immune response in the body. They also function as scavengers and destroy foreign bacteria and fungi detected in the body.

What is the function of basophils? ›

Basophils are a type of white blood cell that works closely with your immune system to defend your body from allergens, pathogens and parasites. Basophils release enzymes to improve blood flow and prevent blood clots.

What are WBC also called? ›

WBCs are also called leukocytes. They help fight infections. There are five major types of white blood cells: Basophils. Eosinophils.

What are the 7 types of blood cells? ›

Blood contains many types of cells: white blood cells (monocytes, lymphocytes, neutrophils, eosinophils, basophils, and macrophages), red blood cells (erythrocytes), and platelets.

What is the structure of WBC? ›

Structure of WBC WBCs are produced from the bone marrow and found in the blood and lymphatic system. A WBC has a nucleus, which often large and lobed, and it helps to distinguish WBC from the other blood cells. Each WBC structure consists of a nucleus, cytoplasm and cell wall [1], as shown in Fig.

What is neutrophils function? ›

Neutrophils are the primary mediators of the rapid innate host defense against most bacterial and fungal pathogens that occurs before the complex humoral and lymphocyte cellular processes of acquired immunity can be brought to bear on an infection.

What are the 3 functions of white blood cells? ›

White blood cells carry out their defense activities by ingesting foreign materials and cellular debris, by destroying infectious agents and cancer cells, or by producing antibodies.

What is function of WBCs Class 11? ›

WBC accounts for about 1% of the body's blood but they play an integral role in body functioning. They are also called leukocytes. And their function is to defend the body against infections. They can be considered as the immunity cells.

Where are WBC formed write the main function of it? ›

Produced in the bone marrow, they defend your body against infections and disease. But, when there are too many white blood cells, it usually means you have infection or inflammation in your body. Less commonly, a high white blood cell count could indicate certain blood cancers or bone marrow disorders.

What are the 5 types of WBCs? ›

Types of white blood cells are granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells).

What are the 7 types of blood cells? ›

Blood contains many types of cells: white blood cells (monocytes, lymphocytes, neutrophils, eosinophils, basophils, and macrophages), red blood cells (erythrocytes), and platelets.

What are the functions of WBC Class 10? ›

White Blood Cells (WBCs) are the defence system of our body. They help in fighting against the germs that enter into our body by producing antibodies.
  • White Blood Cells (WBCs) are the defence system of our body.
  • They help in fighting against the germs that enter into our body by producing antibodies.

What is the function of WBC in the body Class 12? ›

WBC – White blood cells are also called leukocytes or leucocytes. They are cells of the immune system, which is mainly responsible for: Protecting and fighting against invading pathogens.


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