Q.17 Which one of the following statements is INCORRECT about hybridoma
production?
(A) Hybridoma cells can use hypoxanthine and thymidine
(B) DNA synthesis in myeloma cells is blocked by aminopterin
(C) Hybridoma cells are made to produce polyclonal antibodies
(D) Polyethylene glycol is used to fuse myeloma cells to B-cells

Hybridoma Production: Identifying the Incorrect Statement (GATE BT Exam Guide)

Hybridoma technology enables monoclonal antibody production by fusing B-cells with myeloma cells. The incorrect statement among the options is that hybridoma cells produce polyclonal antibodies, as they actually generate monoclonal ones.​

Correct Answer

Option (C) is incorrect: Hybridoma cells are made to produce monoclonal antibodies, not polyclonal ones.​

Option Explanations

• (A) Correct: Hybridoma cells inherit HGPRT from B-cells, allowing use of hypoxanthine and thymidine in the salvage pathway for survival in HAT medium.​

• (B) Correct: Aminopterin blocks de novo nucleotide synthesis in myeloma cells (lacking HGPRT), causing their death while hybrids survive.​

• (C) Incorrect: Hybridomas produce monoclonal antibodies specific to one epitope, unlike polyclonal mixtures from multiple B-cell clones.​

• (D) Correct: Polyethylene glycol (PEG) fuses myeloma cells with spleen B-cells to form stable hybridomas.​

HAT Selection Mechanism

HAT medium (hypoxanthine, aminopterin, thymidine) selectively grows hybrids:

• Unfused B-cells die naturally due to limited lifespan.

• Myeloma cells die from aminopterin-blocked DNA synthesis without HGPRT.

• Hybrids thrive via B-cell HGPRT for salvage synthesis.​