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Short answer
U-2 OS (also written U2OS or U-2OS) is a human osteosarcoma cell line. ATCC lists it as HTB-96: an adherent line with epithelial morphology, derived in 1964 from the tibia of a 15-year-old female donor. A cell line is cells from one origin that can be grown and passaged repeatedly in culture, so reports should name the supplier, catalogue number and identity checks.
What is a cell line? Definition and scope
A cell line is a population of cells from one origin that can be grown and passaged in culture over many generations, so different labs can work on the same biological material. The wider field context is in what is cell biology, and the same definition is applied on the sibling guides for K562 and MC38. This page uses U-2 OS as the worked example.
Three terms from the International Cell Line Authentication Committee (ICLAC) matter whenever a cell line is named in a paper or an order. ICLAC writes that “the aim of authentication is to confirm or verify the identity of a cell line”, that a misidentified cell line “no longer corresponds to the donor or species from which it was originally established”, and that cross-contamination “occurs when that foreign material consists of cells from another culture”. ICLAC also maintains a Register of Misidentified Cell Lines.
What U-2 OS is
The ATCC product page for HTB-96 describes U-2 OS as a cell line with epithelial morphology “derived in 1964”, growing adherent. It lists the tissue as human bone (tibia), the disease as osteosarcoma, and the donor as a 15-year-old White female. ATCC describes the cells as chromosomally highly altered, with chromosome counts in the hypertriploid range, and lists the line as a suitable transfection host.
Cellosaurus (entry CVCL_0042) agrees on a female donor aged 15 at sampling and gives the original publication as Ponten and Saksela (1967), “Two established in vitro cell lines from human mesenchymal tumours”. It records the amelogenin result as X and lists many engineered child lines derived from U-2 OS.
How it is cultured in practice
ATCC states these conditions: ATCC-formulated McCoy’s 5a Modified Medium (30-2007) with fetal bovine serum to a final concentration of 10%, at 37 °C with 5% CO2, medium renewal two to three times a week, and a subcultivation ratio of 1:3 to 1:6. For freezing, ATCC specifies complete growth medium with 5% (v/v) DMSO, with the cells held below -130 °C, preferably in liquid nitrogen vapor. See fetal bovine serum for the background term.
ATCC reports mycoplasma as not detected in its current quality control and notes that mycoplasma contamination was detected and eliminated in 1972.
Names and identifiers: one line, many spellings
The same line appears under several names, which is why a methods section needs more than a short name.
| Item | What the source records | Source |
|---|---|---|
| Synonyms | U-2 OS; U-2OS; U-2-OS; U2-OS; U20-S; U20S; 2T | Cellosaurus |
| Misspellings listed in databases | U-205 and U205, listed as misspellings | Cellosaurus |
| Cellosaurus accession | CVCL_0042 | Cellosaurus |
| Repository catalogue numbers with STR profiles | ATCC HTB-96; DSMZ ACC-785; ECACC 92022711; CLS 300364; KCLB 30096 | Cellosaurus |
| Origin | Bone (tibia), osteosarcoma, female donor aged 15 | ATCC; Cellosaurus |
| Growth | Adherent; epithelial morphology | ATCC |
The RRID format for a Cellosaurus line uses the CVCL_ prefix, so this line is cited as RRID:CVCL_0042. The authentication of key resources entry covers the funder expectation behind reporting identity checks.
Where sources disagree, and what to record
| Point | What the sources say |
|---|---|
| Doubling time | Cellosaurus lists about 36 hours from one publication and about 25-30 hours from DSMZ (ACC-785). ATCC’s product page does not give a doubling time. |
| Biosafety wording | The ATCC page for HTB-96 contains both a BSL 1 label and a sentence about a “biosafety level 3 product” in the product-sheet notice. Read the supplier’s current product sheet for the line you actually hold rather than relying on a summary. |
| Origin year | ATCC gives 1964 for derivation; Cellosaurus cites the 1967 publication. These are a derivation date and a publication date, not a conflict. |
For a methods section or a purchase record, note the name used, supplier and catalogue number, Cellosaurus accession, passage or lot, the authentication method and the reference profile used, and the mycoplasma test result. ATCC publishes a short tandem repeat (STR) profile for HTB-96 under its quality control specifications, for example amelogenin X, D5S818 11, D13S317 13, D7S820 11,12, D16S539 11,12 and TPOX 11,12. Cellosaurus lists profiles from several repositories, so state which reference your result was compared with.
Common misunderstandings
“U-2 OS and U2OS are different lines.”
Cellosaurus lists U2OS, U-2OS, U-2 OS and other spellings as synonyms of one line. U-205 is listed as a misspelling.
“A line bought from a catalogue is automatically authenticated in your lab.”
ICLAC defines authentication as confirming the identity of a cell line, and a misidentified line no longer matches its original donor. A supplier’s profile documents the stock it sold; your own culture is verified by testing it.
“All sources give the same growth rate.”
Cellosaurus lists about 36 hours and about 25-30 hours from different sources, so cite the source for any figure you use.
FAQ
What is a cell line?
A cell line is cells from one origin that can be grown and passaged in culture repeatedly, so labs can study the same material. U-2 OS is one example, with a female donor aged 15 and osteosarcoma of the tibia.
What is the definition of a cell line, and what does ICLAC add?
The working definition is above. ICLAC adds the vocabulary for checking it: authentication confirms identity, misidentification means the cells no longer match their stated donor or species, and cross-contamination means cells from another culture are present.
What is the U-2 OS cell line?
It is a human osteosarcoma line, ATCC HTB-96, adherent with epithelial morphology, derived in 1964 according to ATCC.
Is U2OS the same as U-2 OS?
Yes. Cellosaurus lists U2OS among the synonyms of CVCL_0042.
Sources
- ATCC, U-2 OS (HTB-96) product page: https://www.atcc.org/products/htb-96 (checked 2026-10-29).
- Cellosaurus, U-2 OS (CVCL_0042): https://www.cellosaurus.org/CVCL_0042 (checked 2026-10-29).
- International Cell Line Authentication Committee, Definitions: https://iclac.org/resources/definitions/ (checked 2026-10-29).
