Walter Nelson-Rees

Walter Nelson-Rees (1929–2009) was an American cell biologist and cytogeneticist who played a crucial role in uncovering widespread cell line contamination and misidentification in the scientific community during the 1970s and 1980s. He is best known for his work on HeLa cell contamination, which led to increased awareness of the issue and the implementation of more stringent cell culture practices and authentication methods.

Nelson-Rees worked at the Naval Biosciences Laboratory in Oakland, California, and later at the University of California, San Francisco. He specialized in identifying and characterizing human cell lines using cytogenetic techniques, such as karyotyping. During his research, Nelson-Rees discovered that many cell lines thought to be unique were, in fact, HeLa cells or were contaminated with HeLa cells.

HeLa cells are highly aggressive and can easily overtake other cell cultures if contamination occurs, leading to misidentification and cross-contamination. Nelson-Rees’s findings raised significant concerns about the validity and reproducibility of numerous studies conducted using these contaminated cell lines.

In 1974, Nelson-Rees and his colleagues published a landmark paper in the journal Science, revealing the extent of HeLa cell contamination and its implications for scientific research. Despite initial resistance from some members of the scientific community, Nelson-Rees’s work eventually led to increased awareness of the issue and the development of guidelines and best practices for cell culture and cell line authentication.

Walter Nelson-Rees’s contributions to the field have had a lasting impact on cell biology research, emphasizing the importance of proper cell culture practices, regular cell line authentication, and the need for vigilance in avoiding cross-contamination to ensure the accuracy and reproducibility of scientific findings.