Question

In hybridoma technology, which one of the following enzymes is absent in the myeloma cells that are used for monoclonal antibody production?

• A. Hypoxanthine-guanine phosphoribosyltransferase
• B. Alanine aminotransferase
• C. Triose phosphate isomerase
• D. Glycosyltransferase

Hint:

HAT medium selection works by exploiting HGPRT deficiency.
Only hybridomas can survive as they combine HGPRT activity (from B cells) with immortality (from myeloma cells).

Answer 1

The Correct Option is A

Step 1: In hybridoma technology, myeloma cells are fused with B-cells to produce hybrid cells capable of indefinite growth and antibody production.
Step 2: Myeloma cells used in this process are deliberately deficient in the enzyme Hypoxanthine-guanine phosphoribosyltransferase (HGPRT).
Step 3: This allows for the selection of hybridoma cells in HAT medium, because unfused myeloma cells die (due to HGPRT deficiency) and unfused B-cells die naturally as they cannot grow indefinitely.
Step 4: Only fused hybridomas survive and proliferate. Hence the absent enzyme is HGPRT.