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Granulocyte Isolation from Whole Blood: Types of Granulocytes and Granulocytes Function

Blood is made up of many different components. Within a whole blood sample, you will find the presence of granulocytes, plasma, monocytes, lymphocytes, platelets, red blood cells, etc. When attempting to study the functions of one component, it must first be isolated from the rest of its counterparts. One cell type that contributes to the immune response is the granulocyte. Granulocytes help with critical immune tasks like destroying harmful pathogens in the body and bolstering inflammation as a defense mechanism.

What is a Granulocyte?

A granulocyte is a form of white blood cell with very small granules that contain specific proteins or enzymes. They are the most abundant type of white blood cell in the body and can be subcategorized into specific subtypes like neutrophils, eosinophils, and basophils. They develop in the bone marrow and only live for a few days, entering the bloodstream in their last few hours of living. On average, granulocytes should make up around two-thirds of the body’s total white blood cells.

Granulocytes Function

Granulocytes are a key player in the immune response to infections and allergic reactions. Granulocytes will navigate to the site of the problem, then release the proteins and enzymes contained within their granules to fight back against the pathogens. It’s important to have an appropriate number of granulocytes in your body during an infection.

If you have too few granulocytes, a condition called granulocytopenia, you can be more susceptible to infections. Also called agranulocytosis, granulocytopenia is typically caused by blood cell-related disorders such as leukemia or anemia, conditions that prevent the body from creating new blood cells or that cause harm to the existing population.

At the other end of the spectrum, a high granulocyte count is called granulocytosis. Granulocytosis is typically a symptom of infection rather than a cause. When the body is experiencing a major infection, cancer, or autoimmune disease, granulocyte counts will be abnormally high. While this can be a helpful measure for identifying infection, it can also imply the presence of serious or dangerous infections. For example, granulocytosis is the primary symptom of CML, or chronic myelogenous leukemia. This is a rare blood cell cancer that stops cells in the bone marrow from properly maturing, which leads to an increase in immature granulocytes in the bloodstream.

Types of Granulocytes

There are three different types of granulocytes within the human body. They are characterized as belonging to the granulocyte family due to the presence of enzyme-containing granules in their cytoplasm.


Neutrophils are the most common form of granulocyte. Their main function is to consume bacterial cells to fend off infections. This allows the body to dispose of dangerous cells and clean up potential pathogens. Within its lifetime, each neutrophil can clear somewhere between 5 and 20 bacteria. Neutrophils should make up around 50-70% of the white blood cell population.


Eosinophils can play a role across all immune responses in the body. They help to boost inflammation when dealing with allergic responses and other issues.. Eosinophils comprise roughly 1-3% of the body’s total white blood cells.


Basophils are another helper in dealing with allergic reactions and other immune responses. They can pull this off by releasing one of two things to bolster the immune response. First, they can release a histamine that causes inflammation and helps fend off infection. Second, they can release heparin, a blood thinner to help prevent clotting of the blood. Basophils are the least common granulocyte in the body, making up only 0.4-1% of the total white blood cell population.

Granulocyte Isolation Protocol

Granulocytes are generally denser than other T lymphocytes in the body. The different types of granulocytes also require different methods of isolation. Depending on the goal of your research, you may need to purchase specific neutrophil, basophil, or eosinophil isolation products. These products will help you isolate specific cell populations from a larger blood sample.

Isolation of Mononuclear Cells and Granulocytes from Human Blood

To properly extract these cells, you will need to harness blood separation techniques as a first step. Along with granulocytes, there are a multitude of other mononuclear cells which are isolated and studied by scientists. Other T lymphocytes such as CD4+, CD8+ and naïve T cells all serve an integral role in the human immune response.

Using Akadeum’s Microbubbles

Akadeum’s T Cell Isolation Kits allow for quick, gentle, and easy T cell enrichment that is specifically designed to maintain the health and physiology of delicate cells of interest while maximizing retention, delivering a highly enriched population of target cells to enable better science. With Akadeum’s microbubbles, you can quickly and easily interrogate the full sample volume – directly in the sample container – using a fast and easy workflow.

If you are involved in cell isolation research, we’d love to hear from you! We are actively seeking new applications for our microbubble technology and would welcome the opportunity to

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