PEGylation is the covalent attachment of PEG (PolyEthylene Glycol) to molecules (e.g. proteins). It states in wikipedia ("PEGylation"):

The covalent attachment of PEG to a drug or therapeutic protein can "mask" the agent from the host's immune system (reducing immunogenicity and antigenicity), and increase its hydrodynamic size (size in solution), which prolongs its circulatory time by reducing renal clearance

It seems to be a widely used method in phrmacology. (Other medical uses for peg PEG - as a laxative- macrogol, and as an excipient in some drugs.)

However, there is another use for PEG which is to fuse B cells with immortalised myeloma cells in order to produce hybridoma cells for the production of antibodies. That means, PEG have the ability to fuse two cells together.

How then, it's considered safe to use it as a drug? How come it doesn't fuse cells inside the body (when taken orally or intravenously)? Under which conditions is this property (cell fusion) of PEG observable?

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    $\begingroup$ Can you provide a citation for the cell fusion function of PEG? Bear in mind also that PEG is a polymer; molecules of different MW will have different activities, and those bound to another molecule will be different from PEG in free solution, etc. $\endgroup$
    – timeskull
    Commented Aug 4, 2022 at 13:52
  • $\begingroup$ wikipedia "Hybridoma technology".: Once splenocytes are isolated from the mammal's spleen, the B cells are fused with immortalised myeloma cells. The fusion of the B cells with myeloma cells can be done using electrofusion. Electrofusion causes the B cells and myeloma cells to align and fuse with the application of an electric field. Alternatively, the B-cells and myelomas can be made to fuse by chemical protocols, most often using polyethylene glycol. $\endgroup$
    – Ynk
    Commented Aug 4, 2022 at 20:16
  • $\begingroup$ Looking at the indicated protocols, they specify the myeloma cells should be split the day before fusion so they will be in "log phase" that is, constantly dividing. Normal cells don't do this in the body so that may be a factor. $\endgroup$
    – timeskull
    Commented Aug 4, 2022 at 21:14


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