How does North American coral snake antivenin work?

The North American coral snake's venom is a protein. The coral snake antivenin is the binding fragment of an antibody to the snake venom. To make the antivenin, scientists inject the snake venom into healthy horses. The horses make antibodies against the snake venom. The scientists collect and purify the antibodies from the horses' blood. The portion of the antibody that binds to the snake venom is concentrated into the antivenin.  When the antivenin is injected into someone who has been bitten by a coral snake, the antivenin protein binds to the snake venom and neutralizes it.