A peripheral blood mononuclear cell (PBMC) is any

peripheral blood cell Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the ci ...

having a round

nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: *Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucle ...

. These cells consist of

lymphocyte A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic ad ...

s (

T cell A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell r ...

B cell B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype. They function in the humoral immunity component of the adaptive immune system. B cells produce antibody molecules which may be either secreted or ...

NK cell Natural killer cells, also known as NK cells or large granular lymphocytes (LGL), are a type of cytotoxic lymphocyte critical to the innate immune system that belong to the rapidly expanding family of known innate lymphoid cells (ILC) and represen ...

s) and

monocyte Monocytes are a type of leukocyte or white blood cell. They are the largest type of leukocyte in blood and can differentiate into macrophages and conventional dendritic cells. As a part of the vertebrate innate immune system monocytes also inf ...

s, whereas

erythrocyte Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

s and

platelet Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...

s have no nuclei, and

granulocyte Granulocytes are cells in the innate immune system characterized by the presence of specific granules in their cytoplasm. Such granules distinguish them from the various agranulocytes. All myeloblastic granulocytes are polymorphonuclear. They ha ...

s (

neutrophil Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in ...

basophil Basophils are a type of white blood cell. Basophils are the least common type of granulocyte, representing about 0.5% to 1% of circulating white blood cells. However, they are the largest type of granulocyte. They are responsible for inflammator ...

s, and

eosinophil Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. A ...

s) have multi-lobed nuclei. In humans, lymphocytes make up the majority of the PBMC population, followed by monocytes, and only a small percentage of dendritic cells. These cells can be extracted from whole blood or buffy coat samples using a hydrophilic colloid and

density gradient centrifugation In biochemistry and cell biology, differential centrifugation (also known as differential velocity centrifugation) is a common procedure used to separate organelles and other sub-cellular particles based on their sedimentation rate. Although o ...

, which separates the blood into a top layer of plasma, followed by a layer of PBMCs and a bottom fraction of polymorphonuclear cells (such as

neutrophils Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying in ...

and

eosinophils Eosinophils, sometimes called eosinophiles or, less commonly, acidophils, are a variety of white blood cells (WBCs) and one of the immune system components responsible for combating multicellular parasites and certain infections in vertebrates. A ...

) and

erythrocytes Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

. The

polymorphonuclear Granulocytes are cells in the innate immune system characterized by the presence of specific granules in their cytoplasm. Such granules distinguish them from the various agranulocytes. All myeloblastic granulocytes are polymorphonuclear. They hav ...

cells can be further isolated by lysing the erythrocytes.

Basophils Basophils are a type of white blood cell. Basophils are the least common type of granulocyte, representing about 0.5% to 1% of circulating white blood cells. However, they are the largest type of granulocyte. They are responsible for inflammator ...

are sometimes found in both the denser and the PBMC fractions. A high-quality PBMC isolate has a viability over 90% and a low concentration of erythrocytes and granulocytes when processed fresh. Cell numbers and viability can be determined by manual or automated cell count or by using a

flow cytometer Flow cytometry (FC) is a technique used to detect and measure physical and chemical characteristics of a population of cells or particles. In this process, a sample containing cells or particles is suspended in a fluid and injected into the fl ...

. The latter can also be used to determine the percentage of PBMCs compared with other cell types (which should be >85%). If you do not have the capacity to isolate PBMCs, PBMC isolation can be outsourced to a central laboratory service provider. Table 1: Cell types contained within the PBMC compartment and their typical distribution in healthy adults.

Clinical significance

Infections

Recent studies indicate that PBMCs may be susceptible to pathogenic infections, such as '' Ureaplasma parvum'' and urealiticum, ''Mycoplasma genitalium'' and hominis and ''Chlamydia trachomatis'' infections. PBMCs may be also susceptible to viral infections. Indeed, footprints of

JC polyomavirus ''Human polyomavirus 2'', commonly referred to as the JC virus or John Cunningham virus, is a type of human polyomavirus (formerly known as papovavirus). It was identified by electron microscopy in 1965 by ZuRhein and Chou, and by Silverman an ...

and

Merkel cell polyomavirus Merkel cell polyomavirus (MCV or MCPyV) was first described in January 2008 in Pittsburgh, Pennsylvania. It was the first example of a human viral pathogen discovered using unbiased metagenomic next-generation sequencing with a technique called d ...

have been detected in PBMCs from pregnant women and women affected by spontaneous abortion.

Research uses

Many scientists conducting research in the fields of

immunology Immunology is a branch of medicineImmunology for Medical Students, Roderick Nairn, Matthew Helbert, Mosby, 2007 and biology that covers the medical study of immune systems in humans, animals, plants and sapient species. In such we can see there ...

(including

auto-immune In immunology, autoimmunity is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents. Any disease resulting from this type of immune response is termed an "autoimmune disease". P ...

disorders),

infectious disease An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dise ...

hematological malignancies Tumors of the hematopoietic and lymphoid tissues (American English) or tumours of the haematopoietic and lymphoid tissues (British English) are tumors that affect the blood, bone marrow, lymph, and lymphatic system. Because these tissues are all ...

vaccine A vaccine is a biological Dosage form, preparation that provides active acquired immunity to a particular infectious disease, infectious or cancer, malignant disease. The safety and effectiveness of vaccines has been widely studied and verifie ...

development, transplant immunology, and

high-throughput screening High-throughput screening (HTS) is a method for scientific experimentation especially used in drug discovery and relevant to the fields of biology, materials science and chemistry. Using robotics, data processing/control software, liquid handlin ...

are frequent users of PBMCs. In many cases, PBMCs are derived from

blood banks A blood bank is a center where blood gathered as a result of blood donation is stored and preserved for later use in blood transfusion. The term "blood bank" typically refers to a department of a hospital usually within a Clinical Pathology laborat ...

. PBMC fraction also contains progenitor populations, as demonstrated by methylcellulose based colony forming assays. PBMCs have been thought to be an important route of vaccination. PBMCs from cancer patients can be extracted and cultured ''in vitro''. Subsequently, PBMCs are challenged with

tumor antigen Tumor antigen is an antigenic substance produced in tumor cells, i.e., it triggers an immune response in the host. Tumor antigens are useful tumor markers in identifying tumor cells with diagnostic tests and are potential candidates for use in c ...

s such as tumor stem cell antigen. Inflammatory

cytokines Cytokines are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are peptides and cannot cross the lipid bilayer of cells to enter the cytoplasm. Cytokines have been shown to be involved in autocrin ...

are usually added to aid in antigen uptake and recognition by PBMCs.

References

Leukocytes {{Immunology-stub

Clinical significance

Infections

Research uses

See also

References