Ever tried doing a intact mAB analysis? Used to be suuuper hard. On a Q Exactive, its almost approaching the point of being trivial. Optimize a short gradient, optimize the NCE, deconvolute it with Respect --> Boom! Intact antibody mass within a single Da or two of the theoretical. Sure, its harder if you're doing something like an ADC with 30 drugs conjugated to it, but considering where we were just a few years ago? Many instruments still in use can't provide mass accuracy high enough to tell whether an antibody is glycosylated or not (+/-220Da) so we've come a suuuper long way!
One big problem for mAB researchers is that they've never had a good standard. Especially for Orbitrap precision...until now thanks to the National Institute of Standards!
NIST decided to create a great mAB standard. Something that would suffer from very little lot to lot variability (cause they made literally enough for every lab in the world...for years...). And they characterized the crap out of it.
There have been mass spec standards out there, but they have not been this controlled. Point me toward one if I'm wrong, but the ones I've used have had tremendous problems with lot to lot variability and...the information on the antibody is often wrong or vague. How can I check <10ppm mass accuracy on the antibody when the vendor rounds the mass of the antibody off as something like 147,100 Da? Ya can't. You can verify that your Q Exactive is not on fire. That is it.
Wow. This got rambly. Surprise!!
Waters has had a mAb standard suitable for MS for 5 years
ReplyDeleteYeah...suitable...good choice of words!
Delete1) Relatively small lots are produced for all of the commercial mAB standards. If your job is deep antibody characterization and you're using a commercial standard for all of your QC/QA/optimization and your next lot comes in and there are a few -- or several -- differences, this can totally screw up your day...or week... Honestly, these problems aren't all that obvious unless you are looking close, so they may not matter to everyone's research. If you are using a Q-TOF and you only have the sensitivity to see 3 glycoforms and you don't have the fidelity to notice a shift in the distribution of their intensities or see the minor PTM species, the lots probably won't look any different. But for groups doing sensitive characterization of ADCs, who need to know every location of every drug "warhead" and PTM on every immunotherapeutic, this can be a seriously big deal.
NIST made a massive investment to create a standard that won't have to produce a new lot for years and years. It addresses a major shortfall of the commercial suppliers.