Which one of the following statements is $\text{INCORRECT}$ about hybridoma production?
- Hybridoma cella can use hypoxanthine and thymidine
- $\text{DNA}$ synthesis in myeloma cells is blocked by aminopterin
- Hybridoma cells are made to produce polyclonal antibodies
- Polyethylene glycol is used to fuse myeloma cells to $B$-cells