In the immunology lab this week, we tested for the presence of ABO blood group antigens in our saliva.
Apparently, 80% of the population are secretors, but I don’t quite see the point in having these antigens floating around in your spit and other secretions. Does it give some sort of advantage, from an evolutionary point of view? My prof isn’t sure how the antigens get there and why they’re there, and I think she’s getting tired of my questions.
Well, this has been up a couple of hours, so I’ll WAG it.
WAG: the antigens just seep into your saliva, since they are throughout your blood and sera. Or in other words, the body doesn’t go to the trouble of separating them out of your saliva. There doesn’t have to be an evolutionary advantage, they can be neutral or of minimum effect (ie, have small energy cost to have them or to separate them out). [/VERBOSE WAG]
There’s no real purpose for having them in our blood - the only reason we care about them is because of transfusions and whatnot. They don’t really do anything for us. So why would there be a reason for having them in our saliva?