MRC-5

MRC-5 (Medical Research Council cell strain 5) is a diploid cell culture line composed of fibroblasts, originally developed from the lung tissue of a 14-week-old aborted Caucasian male fetus. The cell line was isolated by J.P. Jacobs and colleagues in September 1966 from the seventh population doubling of the original strain, and MRC-5 cells themselves are known to reach senescence in around 45 population doublings.
Applications.
MRC-5 cells are currently used to produce several vaccines including for hepatitis A, varicella and polio.
Culture and society.
During the COVID-19 pandemic, anti-vaccination activists misidentified MRC-5 as an ingredient of the COVID-19 vaccine AZD1222. The fetal cell line used in the manufacturing of AZD1222 is HEK 293, though the cells are filtered out of the final product.