To Create Cellular Factories for Monoclonal Antibody Production, Cells Derived

Multiple Choice

To create cellular factories for monoclonal antibody production, cells derived from an immortalized B lymphocyte cell line (M) are cultured together with antibody-secreting B lymphocytes (B) on a so-called HAT medium. The medium contains an inhibitor of DHFR, an enzyme essential for de novo nucleotide biosynthesis. Additionally, it contains substrates for the only alternative nucleotide biosynthetic pathway called the salvage pathway. The enzyme HGPRT is essential for the salvage pathway. One of the cells mentioned above lacks the gene encoding one of the enzymes mentioned. Considering the role of the HAT medium in selecting for hybrid cells that are both immortalized and secrete antibodies, which cell (B or M) do you think is missing an enzyme? Which enzyme is missing in this cell?

A) M - DHFR
B) M - HGPRT
C) B - DHFR
D) B - HGPRT