Cell culture is a fundamental research tool that enables scientists to probe the complexities of biology, establish drug development assays, produce recombinant proteins, and more. Choosing the most appropriate cell line to culture is often a balance between experimental need and accessibility. 

Often scientists choose to culture immortalized cell lines since they offer several advantages, including perpetual growth and widespread availability. However, immortalized cells lines do not recapitulate the biology of normal healthy tissue-specific cells. Beyond the scope of investigating cancer, immortalized cell lines offer a limited purview. 

In contrast, primary cells directly isolated from the tissue of interest provide a more realistic model of human health and disease because their physiology more closely resembles the healthy tissue from which they were extracted. Isolating cells from fresh human tissue is not practical for most laboratories and requires access to medical facilities or specialized approvals. 

Tissue architecture is complex, comprising heterogeneous cell types in various cellular states. Purifying a homogenous population of cells from tissues requires numerous steps including specialized isolation protocols, tagging cells with cell-type-specific markers, and cell sorting. Culturing a purified population of primary cells depends on optimized cell culture media for each cell type and state. 

MilliporeSigma recently partnered with PromoCell, an industry-leading manufacturer of more than 100 human cells types, to provide scientists with a broad range of ethically sourced, verified, and reliable human primary, stem, and blood cells. Each primary cell is collected from consenting donors at medical centers. Deidentified donor information, such as biological sex, age, and ethnicity for each cell line is available, enabling population-level disease modeling. 

Each primary cell also undergoes stringent quality control procedures to ensure correct cellular identity, growth, and differentiation performance. PromoCell supplies a broad range of primary human cells, including chondrocytes, endothelial, epithelial, fibroblast, follicle dermal papilla, keratinocyte, melanocyte, osteoblast, pericyte, preadipocyte, and smooth muscle cells. Scientists at PromoCell validate each cell line for cell type-specific markers, cell morphology, population doubling time, and proliferation capacity. They also test the purity of each cell line to ensure the absence of HIV-1, HIV-2, HBV, HCV, fungi, mycoplasma, and other bacteria.

The idea of providing primary cells from healthy donors that are free of contamination extends to human stem and blood cells provided by MilliporeSigma and PromoCell. Adult stem and blood cells are collected from normal human bone marrow, as well as cells from umbilical cord tissue, placenta, adipose tissue, peripheral blood, and cord blood. This ensures that each stem and blood cell reflects a healthy tissue state uninfluenced by biological disease programs. 

The success of cultured primary cells depends on cell-type specific optimized medium. Defined media ensures that only the desired cell type will thrive in culture. Thus, each cell line comes with optimized differentiation media systems. These systems replace serum with defined media components whenever possible, which guards against the unpredictable effects of indeterminate compounds found in serum concoctions. 

For researchers who are interested in isolating cancer cells, MilliporeSigma and PromoCell provide a variety of primary cancer culture solutions. These media and reagents are optimized to selectively promote the culture of malignant cells derived from patient xenografts or primary tumors within just 4-6 weeks. Although cancer cell lines are readily available for most cancer types, they are often influenced by cell culture induced changes and do not adequately reflect the behavior of cancer in patients. MilliporeSigma and PromoCell’s defined serum-free formulations support the derivation of three-dimensional cancer sphere formation and ensure the highest purity of derived primary, stem, blood, and cancer cells.