The key difference between monocyte and lymphocyte is that monocyte is a white blood cell that kills antigens through phagocytosis while lymphocyte is a white blood cell that produces antibodies and neutralizes antigens.

White blood cells protect us from the infections and foreign particles that make us ill. Moreover, there are several types of white blood cells in our body. They are monocytes, lymphocytes, neutrophils, basophils, and eosinophils. Monocytes are the largest type of white blood cells involved in innate immunity. They engulf foreign particles by phagocytosis and protect us from infections. On the other hand, lymphocytes are the main type of immune cells in the lymphatic system. They participate in adaptive immunity by forming antibodies. However, both cells are similarly important immune cells. Hence, this article focuses on the difference between monocyte and lymphocyte.

CONTENTS

1. Overview and Key Difference
2. What is Monocyte 
3. What is Lymphocyte
4. Similarities Between Monocyte and Lymphocyte
5. Side by Side Comparison – Monocyte vs Lymphocyte in Tabular Form
6. Summary

What is Monocyte?

Monocyte is a white blood cell present in the vertebrate immune system. It is also a phagocyte. In fact, they are the largest type of white blood cells that account for 2-10 % of the total white blood cells in the bloodstream. Monocyte has an oval-shaped or bean-shaped nucleus and non-granulated cytoplasm. Moreover, monocyte can differentiate into macrophages and myeloid lineage dendritic cells. Dendritic cells are antigen-presenting cells, while macrophages are phagocytic cells. Monocyte production occurs in the bone marrow from monoblasts, and they circulate in the bloodstream.

Figure 01: Monocyte

Monocyte can engulf foreign particles and destroy them through phagocytosis. Furthermore, monocytes carry out antigen presentation and cytokine production.

What is Lymphocyte?

A lymphocyte is a type of white blood cell which acts as an immune cell in the immune system. Lymphocytes are present in the blood as well as in the lymph tissue. Indeed, lymphocytes are the main type of cells found in the lymphatic system.

There are three types of lymphocytes as T lymphocytes, B lymphocytes, and natural killer cells. Natural killer cells recognize and destroy altered cells or cells that have been infected by viruses. B cells produce antibodies which recognize foreign antigens and neutralize them. B cells have two types: memory B cells and regulatory B cells. Furthermore, there are two types of T cells. One type of T cells produce cytokines that induce the immune response while the second type produces granules that are responsible for the death of the infected cells. Lymphocytes, mainly T and B cells, produce memory cells which provide long-lasting immunity against specific pathogens. Lymphoid stem cell produces lymphoblasts, and the lymphoblasts give rise to lymphocytes.

Figure 02: Lymphocyte

The normal level of lymphocytes in the blood of an adult is 1,000 and 4,800 lymphocytes in 1 microliter (µL). In a child, it is between 3,000 and 9,500 lymphocytes in 1 µL of blood. Moreover, the decreased level of lymphocytes indicates a sign of a disease.

What are the Similarities Between Monocyte and Lymphocyte?

• Monocyte and lymphocyte are two types of white blood cells.
• Moreover, their production occurs in the bone marrow.
• They are found in the bloodstream and the lymphatic system.
• Furthermore, they are agranulocytes.
• Both cells contain a nucleus. Hence, they are mononuclear cells.

What is the Difference Between Monocyte and Lymphocyte?

Monocyte is a type of white blood cell that carries out phagocytosis and destroys antigens. On the other hand, the lymphocyte is a type of white blood cell that produces antibodies and involves in adaptive immunity. So, this is the key difference between monocyte and lymphocyte. Furthermore, a significant difference between monocyte and lymphocyte is that the monocytes are the largest type of white blood cells, while lymphocytes are smaller than monocytes.

Moreover, there are two types of monocytes as macrophages and dendritic cells, while there are three types of lymphocytes, namely B cells, T cells, and natural killer cells.

The below infographic summarizes more facts on the difference between monocyte and lymphocyte.

Summary – Monocyte vs Lymphocyte

Monocyte and lymphocyte are two types of white blood cells. Both are mononuclear cells. Moreover, they are agranulocytes. Monocyte is the largest white blood cell, and it is a phagocyte. Lymphocytes are the main type of immune cells in the lymphatic tissue. Monocytes take part in innate immunity while lymphocytes take part in adaptive immunity. Both types originate in the bone marrow. But, monocyte comes from monoblast while lymphocyte comes from lymphoblast. Monocytes kill antigens through phagocytosis while lymphocytes produce antibodies and neutralize antigens. Therefore, this is a summary of the difference between monocyte and lymphocyte.

Reference:

1. Silva, Joana Cavaco. “Lymphocytes: Levels, Ranges, and Functions.” Medical News Today, MediLexicon International, Available here.
2. Raymaakers, Karen. “How Monocytes Function in the Body.” Verywell Health, Verywell Health, 2 July 2019, Available here.

Image Courtesy:

1. “Blausen 0649 Monocyte (crop)” By Blausen.com staff (2014). “Medical gallery of Blausen Medical 2014”. WikiJournal of Medicine 1 (2). DOI:10.15347/wjm/2014.010. ISSN 2002-4436 (CC BY-SA 4.0) via Commons Wikimedia
2. “SEM Lymphocyte” By Unknown photographer/artist (False color modifications made by myself–DO11.10) – Dr. Triche National Cancer Institute (Public Domain) via Commons Wikimedia

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