Human primary cells are cells taken from living human beings and cultured. These cells retain the differentiation of the original cells taken in a biopsy sample and can be used in a wide variety of types of research. Many laboratories that sell cell cultures provide human primary cells by request and they usually list the products they offer in a catalog. Special types of cultures are available for custom orders if a researcher has very specific needs.
Collecting human primary cells starts with a sample from a subject. Some labs rely on subjects who donate tissue specifically for scientific research after signing paperwork, indicating that they have been informed about the type of research that will be done and how their cells will be used. These donors are screened carefully to make sure they are suitable and the lab may also recruit rare donors to ensure a steady supply of access to unusual tissue types. Other labs may use leftovers from biopsy samples taken for diagnosis and treatment to cultivate primary cells.
Human primary cells are not immortalized. After a set number of divisions, the cells will become exhausted and the culture will die. Typically, the lab cultures the biopsy sample long enough to confirm that it is viable and then freezes it. When a researcher needs cells, frozen vials are shipped and the researcher revives the culture. Being able to freeze cells allows labs to keep human primary cells in stock to meet the demand from researchers.
Both healthy and diseased cells can be cultured. This includes everything from bone marrow to tumor cells. The cells are carefully screened and tested to ensure that scientists are being supplied with the cell types they expect. Contamination can arise in a primary human cell culture and special care is taken to avoid and screen for common contaminants. This is done to prevent costly research mistakes, such as assumptions that are based on findings made with a contaminated cell culture.
Culturing cells can be a challenge. Some primary human cells are easy to grow and they can handle a variety of growth media and conditions. Others are more particular and may require special treatment. Most labs have standardized manuals that they use for cell cultures. Standardization reduces the risk of contamination and ensures that researchers are provided with consistent cultures and service. Consistency is critical for most scientific research. Small variations in lab procedures can result in major skews to research projects and their outcomes.