Hi James,
I would largely agree with Cindy: in my experience, different antibody conjugates have different stabilities, even in 50-100% stabilizer (though the stabilizer definitely at least doubles lifetime relative to only W buffer). For example, the CD38 clone I use is stable for >1yr (maybe even 2yr), whereas the CD85j clone I use sometimes starts fading around 5mo even in 50:50 stabilizer:W buffer.
I have seen *some* prep to prep variability in lifetime, but the qualitative trends are always the same: CD85j fades early, CD38 lasts longest, etc.
Regarding metal selection:
1) I've only worked with the Fluidigm 209Bi conjugates, which have been fine for >6mo (longest I've had a given tube....I haven't done actual lifetime studies).
2) La139 on the other hand, I personally try to avoid using: I have had some problems with it. I can definitely get antibodies labeled with it, but I usually see higher background (streaking) and often reducing signal intensity over the order of months. I'm not sure if La139 just isn't as stable somehow in the DTPA chelator on the MAXPAR polymer, or what, but it's been a lot touchier for me than any of the other Ln metals.
3) Indium has been no problem....goes in easily, is stable. But remember that it's "dimmer" than the Lanthanides: you'll want something fairly abundant like CD45, CD57, CD8, or HLADR, for best resolution. I haven't measured O16 oxide signal directly, but it would spill into the Xe region where you don't have any probes anyway.
4) Yttrium also hasn't been a problem for us, the few times we've labeled with it. Again, 89Y is even dimmer than Indium, so take that into account with your marker choice. Also, see this recent discussion on in-house vs Fluidigm 89Y conjugates:
viewtopic.php?f=7&t=3Mike
Mike