Explaining how antibodies work

As part of the fundraising effort on Indiegogo was a blitz through the various pet-centric blogs and websites KA found on the wide world of the internet. PER, KA, and i all took a set of websites and wrote directed emails to ask for help spreading the word of the fundraising to a broader audience. Of the dozens of blogs/websites i have written to, i've gotten two replies thus far (the writing begun around Christmas, we are now 5 days into the New Year). One reply was a request to remove the recipient from our mailing list, and the other was an offer to help along with directed questions about the work and drugs that CanFel is trying to bring to veterinary medicine, specifically, questions about antibodies and how they work.

So, over a rapidly cooling mug of coffee, the following is what i wrote back:

One good way of thinking about antibodies is this. 

First, some ground rules. Antibodies are designed to target cellular proteins and, through the binding of the cellular proteins, affect the cellular protein's function in one of three ways: activate the protein, inhibit the protein, or do nothing. Obviously, the do nothing antibodies are not much good for therapeutics 8). However, the activating or inhibitory antibodies are of therapeutic usefulness, as they can be used to tip the biological balance of cells. 

Second, cellular proteins are outside in signal transducers in the most part. They tell the cells they are on what is going on outside and if the cell should grown, arrest growth, or even self-destruct (a very important biological function actually, but that is for another time perhaps). Aside from signal transduction, some cellular proteins also act to stabilize cells on whatever surface they are sitting on, or act as treads so a cell can have "traction" as they move, or act as tension modifiers to govern how rigid a cell is.

Third, cellular proteins are actually highly mechanical in form and function. For one protein to interact with another protein, there must first be compatibility in form, a lot of time, the interaction of the tumblers in a lock and the key designed for the lock is used to illustrate the importance of form in protein interaction. After the compatibility in form is satisfied, the proteins interact, and the interaction will then send a signal into the cell. This signal is generally triggered by a secondary mechanical event. This second event could be a clustering of proteins, assembling a macro-molecule that is now capable of signal transduction, or a physical change in the protein's shape so that a previously hidden part of the protein is now accessible for function.

So, here is where the antibody comes in. An antibody is also a protein, so it is designed to interact with its target in a specific way. When an antibody is, for example, interacting with a protein in the region of the protein important for that protein's interaction with other proteins, the antibody can effectively block the protein interaction by acting like a piece of gum stuck into a lock and blocking the key's entry or something more subtle, like padding a few tumblers so they are stuck in one position or move too much or too little and jam the lock. The antibody can also bind to a protein in such a way that it acts as a clamp, so when the protein is activated to undergo a mechanical change to transduce a signal, the antibody - as a clam - has restricted the ability of the protein to undergo mechanical change.

So now, lets go to a real world example. Take the lights in your house. They are operated by a switch. The switch is a binary function, on or off. Your house, in essence, is like a cell. When it is tumorous, it has all its lights on. When it is normal, some lights are on, some lights are off. So, how do you go about preventing the lights from all coming on? Well, you can terminate the electricity. That is a very efficient way to kill the lights (as it were), but then you will be in the dark. An antibody, in essence, gives you a tool that allows you to disable certain switches. For example, you can have an antibody that is specific to a circuit breaker - shutting off entire set of switches - or antibody to a specific set of switches - shutting off only certain lights. These antibodies would behave in such a way that you can't physically turn on the switch or it will disable the wires to which the switch goes so that, even if the switch is flipped, no electrical signal is sent.