I made a brief mention of this article yesterday, but I wanted to highlight it. It’s a look, from Nature News, at the broader implications of the antibody problem in research. Antibodies are, of course, universal reagents in molecular biology assays. If you suddenly declared their use illegal, the field would just collapse. But we can’t live with ’em, either, because a really significant percentage of the antibodies used are not as good as they should be. A really disturbing percentage of the scientific literature is (at the very least) complicated by this problem, and some of it is flat-out invalidated by it.
As has been mentioned here several times, the same goes for small-molecule chemical probes, too, and how. That problem is, in principle, a bit more solvable (and I’ve been hearing about some efforts to try to help solve it – more on that as it develops). Small molecules are easier to assay for purity and identity, for one thing, and compared to antibodies, there are a lot fewer of them. The article estimates that there are around 300 companies selling something like two million antibodies. Which of these do what they’re advertised to do, and under what conditions, well. . .that’s hard to say:
Scientists often know, anecdotally, that some antibodies in their field are problematic, but it has been difficult to gauge the size of the problem across biology as a whole. Perhaps the largest assessment comes from work published by the Human Protein Atlas, a Swedish consortium that aims to generate antibodies for every protein in the human genome. It has looked at some 20,000 commercial antibodies so far and found that less than 50% can be used effectively to look at protein distribution in preserved slices of tissue5. This has led some scientists to claim that up to half of all commercially available antibodies are unreliable. . .
. . .Abgent, an antibody company based in San Diego, California, and a subsidiary of WuXi AppTec in Shanghai, China, tested all of its antibodies about a year ago. After reviewing the results it discarded about one-third of its catalogue.
So that should give you a rough estimate, and I don’t think that many experienced assay development folks will be surprised. The people that are surprised, as usual, are the ones who just order out of the catalog and believe what’s on the label. As the article mentions, a lot of people shop on price and speed of delivery, which (you’ll be shocked to hear) are variables that don’t always correlate well with reagent quality. And there are a lot of resuppliers out there, so even if you buy half a dozen antibodies against the same protein from different outfits, you may have only bought two. Or one. Who knows? And if you use up your supply of one that’s working for you and re-order, will the new batch be the same as the old one? Who knows?
There are several online resources that are trying to address this problem (they’re listed in the article), but many people don’t even know about them. And as long people have the attitude that one (now more cautious) scientist expressed in the piece, the crappy reagents will continue to be sold. “I wasn’t trained that you had to validate antibodies;” he says, “I was just trained that you ordered them.”