Raji is the first continuous human cell line of hematopoietic origin.^[1] The Raji cell line is widely used as a transfection host.^[2]

Raji cells were derived from the B-lymphocytes of an 11-year-old Nigerian Burkitt lymphoma male patient in 1963 by R.J.V. Pulvertaft and was further worked on by B.O. Osunkoya (University College Hospital, Ibadan, Nigeria).^[3][4]

The Raji cell line is categorized as lymphoblast-like. The culture medium used to grow Raji cells is RPMI supplemented with serum. Some characteristics of Raji cells include a lack of differentiation, illustrated by the formation of large aggregations of hundreds of individual cells. The cells are relatively small in diameter (5-8 μm), have irregular indented nuclei, and almost extensive cytoplasm with free ribosomes which tend to clump.^[5] Raji cells grow as single, non-motile, free-floating (non-adhesion) individuals or doublets to glass. Some cells look elongated, pear-shaped with larger, multinucleate, round cells.^[5]

The Raji cell line produces an unusual strain of Epstein–Barr virus, which both transforms cord blood lymphocytes and induces early antigens in the cells. Translocations between chromosomes 8 and 22 have occurred in all three variations of the Raji cell line, but some cells synthesize immunoglobulin M with light chains of the kappa type, in contrast to the usual concordance between a translocation involving chromosome 22 and lambda chain synthesis. Both kappa genes and one lambda gene are rearranged. These findings indicate either that translocation may occur as a separate event from immunoglobulin gene rearrangement or that the proposed hierarchical sequence of immunoglobulin gene rearrangements is not always adhered to. The data also imply that in cells containing a translocation between the long arm of chromosome 8 and a chromosome bearing an immunoglobulin gene, alteration of cellular myc expression may occur regardless of the immunoglobulin gene that is expressed.^[6] The cells grow in a suspension, are diploid, and are lymphoblastoid in morphology.