Correct option is D
Explanation-
Statement A: "Monoclonal antibodies are the product of a single stimulated B-lymphocyte." - CORRECT
Monoclonal antibodies are produced by a single clone of B lymphocytes, hence all are identical and specific to the same epitope.
Statement B: "To generate large quantity of monoclonal antibodies, a normal stimulated antibody producing B cell is fused with a long-lived B cell tumor." - CORRECT
This is the basis of hybridoma technology. A short-lived B cell is fused with a myeloma (tumor) cell to obtain a hybridoma, which is both immortal and produces a specific antibody.
Statement C: "The hybridoma generated for antibody production is selected on HAT medium." - CORRECT
HAT medium (Hypoxanthine-Aminopterin-Thymidine) allows selection of only hybrid cells because myeloma cells are HGPRT⁻ and die in HAT medium. B cells die naturally in culture, only fused hybridomas survive.
Statement D: "For HAT selection of hybridoma, the antibody-producing B cells are pre-treated with 8-azaguanine to block salvage pathway of DNA synthesis." - INCORRECT
This statement reverses the procedure. It is the myeloma (tumor) cells that are pre-treated with 8-azaguanine, which selects for HGPRT⁻ mutants. These HGPRT⁻ myeloma cells cannot survive in HAT medium unless fused with HGPRT⁺ B cells (which contribute the functional salvage pathway enzyme). B cells are not treated with 8-azaguanine.
Correct Answer: Option D – Incorrect Statement
