LLC-MK2 (Original) Cells

LLC-MK2 is a continuous epithelial cell line established from the renal tissue of adult rhesus monkeys (*Macaca mulatta*). This cell line was originally isolated in the 1950s through the trypsinization of pooled kidney tissue from six rhesus monkeys. LLC-MK2 cells display adherent growth characteristics and have been extensively used in virology due to their high susceptibility to various viruses, including bovine viral diarrhea virus 1, human poliovirus 1, and human coxsackievirus B4. The cell line's origin and virus susceptibility make it an ideal model for studying viral replication and cytopathogenic effects.

The LLC-MK2 cell line is known for its ability to be cultured in chemically defined, serum-free media, which allows for controlled experimental conditions. Research has demonstrated that these cells can be adapted to serum-free conditions without compromising growth, although initial cultures were maintained in media containing significant amounts of horse serum. The adaptation to chemically defined media is particularly advantageous for virological studies, as it minimizes the variability introduced by serum and supports long-term cell line maintenance. Furthermore, the LLC-MK2 line has been shown to maintain virus sensitivity comparable to primary monkey kidney cells, making it a reliable tool for viral titration and vaccine production studies.

In addition to its role in virology, LLC-MK2 has also been investigated for its tumorigenic potential. Although it exhibits certain transformed characteristics, such as the ability to grow in soft agar, it does not form tumors in in vivo models, suggesting a limited tumorigenic risk. This characteristic further underscores its utility as a model cell line for in vitro studies, while confirming its unsuitability for therapeutic or in vivo applications.