Rich Condit: This raises the issue, again, just briefly, that I was going to comment on earlier. It came up two letters ago, the phrase "correlates of protection", which is a really slippery concept, because it's really easy to make the assumption that "oh, you make antibodies and that's it". No. Or, "you make antibodies to this particular protein, that's all you got to do." No. Immunity that confers protection can be much more complicated than that.
Alan Dove: Everybody with HIV produces antibodies against HIV and they're great antibodies against the virus, and guess what: you still have HIV. So the antibodies in that case are not a correlate of protection. They're just something your body has done. On the other hand, if you're producing great antibodies against measles virus, you're probably protected. That's a very good correlate of protection.
Condit: So figuring out what actually protects you with any particular pathogen is a critical issue and not straightforward.
Brianne Barker: There have been a few times where we've mentioned "neutralizing antibodies" today. Neutralizing is one of the things antibodies can do. That means they can block viruses from getting in to cells or interacting with cells. And so sometimes the correlate is you have to make neutralizing antibodies, not just any old antibodies.
I'm no expert, but usually antibodies mean your body can fight the virus, right?