I recently received a grant from the Animal Behavior Society to buy enzyme immunoassay kits. These kits will be used to measure how cortisol (a “stress hormone”) concentrations influence the ability of trematode parasites to infect California killifish (i.e., are killifish with higher cortisol levels more likely to become infected by their trematode parasites?), and to measure how cortisol concentrations change after infection. Why I’m asking these questions is a good story for another day. Today I want to tell you about how the kits I’ll be purchasing work, because they’re AWESOME:
Below is a picture of a finished plate. In this case, the second and third columns were used as standards. If you look carefully, you can see that they start very faint, and get more bright as you move towards the bottom. This is because more of the kit hormone (bound to the tracer) has been added to each well as you progress down the plate.
Critiques of my explanation for how this kits works are welcome!
Great post, one small comment.
You said the antibodies will bind and unbind until they reach an equilibrium, for any good antibody this is wrong. Theoretically an antibody can unbind after binding, but this will not happen in RT after any reasonable amount of time. To all intents and purposes, once an antibody is bound, it will never unbind in normal conditions.
This is important, because you must not let your sample or the kit hormone bind first and thus get a competitive edge (unless the kit is used just to bind the free left antibodies, this will reduce the dynamic range).