Some are and some are not.

A monoclonal antibody is an antibody (a protein) that is produced by a single clone of cells and has identical antibody molecules on the protein.

REGEN-COV

The one of greatest interest these days is REGEN-COV from Regeneron. It is a combination to two monoclonal antibodies, casirivimab (REGN10933) and imdevimab (REGN10987).

It was developed and tested with the HEK-293T aborted fetal cell lines according to Regeneron’s publication in Cell journal. Another preprint paper in collaboration with Regeneron describes the use of Freestyle 293 cells in the production of REGN10933 and REGN10987, as does this paper in Science journal. We have not been able to verify whether this same production process is used in manufacturing.

Sotrovimab 

Biologics code is VIR-7831. Lenti X-293T cells are used in production; see lines 339 and 415. These cells are a subclone of HEK 293. A subclone is a cell that has been genetically modified from a previous instance. This is often done to alter (enhance or attenuate) a cell’s expression characteristics. In this case, the ‘parent’ HEK-293 cell is modified by a DNA segment to enhance the expression of viral proteins and increase the ease of transfection (infection).

Casirivimab

Uses ACE2-293, HEK-293T, Freestyle 293 cell lines; see above information for REGEN-COV.

Imdevimab

Uses ACE2-293, HEK-293T, Freestyle 293 cell lines; see above information for REGEN-COV.

Bamlanivimab

Biologics code is LY-Cov555. This paper describes the use of HD 293F cells in production of the antibody. The Supplemental Materials of this pre-print paper describe the use of the same cells in production and testing.

Tocilizumab

Also called RoActemra. Produced in Chinese Hamster Ovary (CHO) cells; see Product Review. The Assessment Report also does not describe the use of any aborted fetal cell lines.