There are some good reasons why human serum is one of the most important tools in the world’s laboratories today. Scientists use human serum to grow human cells, more deeply understand the immune system, test the efficacy of drugs, and perform innovative research. Processing human serum for research purposes is complex, but it provides a product that can be used for reliable, repeatable results.
Serum Sample Collection
There are more than 4,000 components in human blood. Each one has a different purpose. The blood’s major components include red and white blood cells, platelets, and plasma. Plasma makes up about 55% of the blood with the other 45% being cells. White blood cells fight infection. Red blood cells carry oxygen. Plasma is a clear, but yellow-tinted watery fluid that holds platelets and cells. It also holds lipids, enzymes, proteins, antibodies, hormones, minerals, vitamins, and blood-clotting factors.
After blood is drawn from donors, lab techs place it in a centrifuge to separate the plasma and the cells. Then the serum is separated from the plasma. The composition of human serum and plasma are similar except for the clotting factors. These are necessary for clotting to occur, especially fibrinogen. Once the lab separates the plasma and human serum from the whole blood, the plasma will retain the fibrinogen, but the serum will not. What does this mean? It means the serum has no clotting ability. It cannot coagulate since it doesn’t contain fibrinogen.
The Makeup of Human Serum
Even though human serum contains no fibrinogen, it does contain carbon dioxide, proteins, minerals, and hormones. Albumin is one of the important proteins found in human serum since it carries steroids, thyroid hormones, and fatty acids in the blood. Serum is also an important source of electrolytes.
The Role of Human Serum and Medications
It is human serum that allows substances to stick to molecules found in the serum. This effectively binds the substance to the blood. This is what allows the transporting of thyroid hormones, fatty acids, and other substances in the serum. It works as a circulating carrier which is why drug manufacturers design medications that bind to proteins like albumin. Once a medication attaches to the albumin, it carries it throughout the bloodstream so that it reaches the target organ or tissue. For example, the curable substances in antibiotics bind to albumin in human serum which is how they are carried throughout the body.
How Human Serum is Used
Researchers use animal serum when they can, but in some cases, it’s not an appropriate substitute. For example, cancer therapy studies and DNA research require the use of human serum samples. Scientists use human serum as a supplement added to culture media since human cells typically require human serum rather than animal serum to grow properly.
Immunity Testing
Human serum yields excellent results when culturing most types of human cells, but particularly for cells associated with the body’s immune system. Researchers use human serum along with lymphocyte culture media. This supports the growth of dendritic cells and lymphocytes which play roles in immunity. Human serum is used by researchers in immunohistochemical staining procedures. This process helps identify foreign antigens that trigger immune responses.
Organ Transplant Compatibility
Yet another use for human serum by scientists in in human leukocyte antigen (HLA) tissue-typing applications. These test the compatibility of donor and recipient organ transplants.
Human Serum in Metabolic Studies
Human off-the-clot serum is used for metabolic studies. Laboratories collect off-the-clot serum by allowing whole blood to coagulate naturally. During this natural process, the blood is not exposed to anticoagulants. Then, a centrifuge is used to separate the serum from cellular components. The serum is then allowed to go through another clotting process. This second clotting by the serum ensures all clotting components are removed. Laboratories centrifuge the serum specimen again, and then draw off the remaining serum which is packaged according to the requirements of the researcher.
Cell Therapy
AB serum is useful in investigating cell therapy applications, tissue engineering, and transplantation. Human AB serum is collected from donors who have AB blood type. It lacks antibodies against both A and B antigens.
Final Thoughts on Human Serum
Human serum is used for research in laboratories around the world. It’s important for scientists to have access to serum samples so they can continue innovative research strategies. Their research is key to discovering new drugs, procedures, and therapies that help improve human health.
Resources
https://pubmed.ncbi.nlm.nih.gov/22230555/
https://www.frontiersin.org/articles/10.3389/fphys.2014.00299/full
https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/human-serum-albumin
