THE HeLa CELL LINE
Most cells senesce and die after a finite number of replications. Some cells, however, can multiply and divide ceaselessly and agelessly. Such cells are immortal cells. Unsurprisingly, cancer cells are often ‘immortal’; Cancer is basically an uncontrolled growth of tissue.
An immortal cell line is termed ‘immortal’ because the cells can replicate indefinitely in culture. In other words, they are the in vitro equivalent of cancer cells.
The first immortal cell line, called the HeLa cell line, was created by Dr. George Otto Gey in 1931. The original cells came from a malignant cervical tumour in the body of a black woman named Henrietta Lacks. Henrietta Lacks died the same year, in October, from the very cancer cells that have since been used to save thousands and thousands of lives.
Neither Lacks nor her family gave permission for Dr. Gey to harvest her cells for the HeLa cell line. Her family members were hurt when they were informed about her cellular immortality. In belated recognition of her posthumous contributions to medical research, October 11 was proclaimed Henrietta Lacks Day.
Now there are many strains of HeLa cells all over the world that have evolved in cell culture, and it is estimated that more HeLa cells have been cultured than were in Henrietta Lacks body to begin with. HeLa cells have even been sent to space.
HeLa cells are so aggressive that they often take over the petri dish and contaminate other samples. The uncontrolled growth of HeLa cells is such a problem that labs cannot use any other cell line when using HeLa cells, for fear of contamination.
The HeLa genome is different from Henrietta Lacks’ genome in many ways, including the number of chromosomes. In fact, due to their non-human number of chromosomes and ability to replicate indefinitely, HeLa cells have even been described as a different, and highly successful species. This, however, has not been widely accepted by the scientific community, but speculation remains.