Neutrophil Isolation: What is a Neutrophil and How to Perform Human Neutrophil Isolation

Granulocytes are white blood cells and come in three forms: neutrophils, eosinophils, and basophils. Neutrophils attack pathogens directly; eosinophils facilitate the body’s inflammatory response, and basophils contain an anticoagulant called heparin that prevents the blood from clotting too quickly.

What is a Neutrophil?

Neutrophils are a critical component of the immune system. Neutrophils are the most prevalent type of granulocyte in the body and make up more than half of the total volume of circulating white blood cells in humans. Neutrophils form in bone marrow from stem cells and typically live in the bloodstream until they are called into action in response to injury or invasion from foreign pathogens.

As the immune system’s first responders to trauma or infection, neutrophils destroy microbes via phagocytosis or secreting antimicrobial agents onto their targets. Receptors on the surface of neutrophil cells detect gradients of chemical traces and allow the neutrophils to follow these tracks to the site of infection.

Due to their small size and high mobility, neutrophils can travel to parts of the body that are out of reach from larger lymphocytes, and play a primary role in attacking harmful bacteria, fungi, or other microorganisms that threaten the host. Moreover, as neutrophils attack pathogens, they release cytokines that support the activity of other cells in the immune system response.

Blood Work Neutrophils

The number of neutrophils present in the body can be an indicator of the health of a patient’s immune system. For example, neutropenia (low neutrophil count) can leave a patient susceptible to infection, even from the normal presence of digestive bacteria. Neutropenia can be caused by a variety of pathology or even treatment, such as chemotherapy or radiation used to treat cancer.

Conversely, high neutrophils mean that a patient has an extraordinary number of neutrophils in their body. Neutrophilia can indicate the presence of pathology or inflammation, which would cause the immune system to pump neutrophils to the site of infection or trauma.

In either case, medical care teams study blood work neutrophils to assess the strength of a patient’s immune system or to detect irregularities in neutrophil count that may be due to underlying pathology.

Traditional Neutrophil Isolation

Given the central role neutrophils play in the immune response, including locomotion, cytokine production, phagocytosis, and tumor cell combat, and the way that a patient’s neutrophil count can provide indications of their overall health, studying neutrophils is of particular concern in immunology.

As with research focused on other cell types, to study the behaviors of neutrophil cells and analyze their potential use in treatment, they must be separated from biological samples and studied in isolation. That said, neutrophils have short lifespans, so effective study requires a quick, gentle, and accurate neutrophil isolation protocol.

Traditional approaches to neutrophil isolation in both mice and human samples typically involve density gradient centrifugation. In density gradient neutrophil isolation protocols, a blood sample is first applied over a medium, and then this solution is run through a centrifuge. Centrifugation causes layers of varying density to form within the solution, and the layer containing neutrophil cells can be separated from the residual cells in the blood sample. The collected neutrophil cells are then washed, counted, and mixed with a buffering solution—this final solution of suspended neutrophils can then be analyzed downstream.

Other methods commonly employed in both mice and human neutrophil isolation protocols involve chemical markers via Fluorescence-activated cell sorting [FACS] or magnetic beads via Magnetic-activated cell sorting [MACS]. While these techniques can yield effective neutrophil isolation, such procedures inevitably subject a sample to intense physical forces that may damage the viability and function of the neutrophil cells themselves. As well, these traditional methods require complex machinery and specialized training that can be cost- and time prohibitive.

Neutrophil Isolation with BACS Microbubbles

Akadeum Life Sciences offers a compelling alternative to these traditional cell isolation methods. Buoyancy-activated Cell Sorting [BACS] using microbubble technology is a gentle and efficient technique capable of processing even the most fragile cell populations at a commercial scale. Akadeum’s BACS products are affordable, easy-to-use, and require no specialized equipment or training, making them especially attractive options for small labs, startups, and research institutions alike.

Neutrophil isolation in both human and mouse samples with BACS microbubble technology involves just a few simple steps. First, a solution of biotinylated antibodies is mixed with a biological sample, and the antibodies label unwanted cells within the population. Then, streptavidin-coated microbubbles are mixed into the sample. The streptavidin on the microbubbles binds to the biotin labels on the unwanted target cells, and the microbubbles and their captured cells float to the surface of the sample for removal. Once the unwanted cells are removed, a pure solution of highly viable neutrophil cells remains in the sample, ready for downstream analysis or treatment applications.

The gentle microbubble cell separation process poses little risk to the health of the neutrophil cells left behind. Moreover, cell sorting with BACS works quickly, allowing researchers to utilize the neutrophil cells for study or treatment before their short lifespan ends.

While Akadeum’s microbubble kits should be a first option for neutrophil isolation protocols, BACS technology can be employed in a range of cell sorting applications. The BACS is a gentle cell isolation method that can be used to isolate rare or fragile cell populations without damaging the cell behavior.

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