Snake venom is composed of several dangerous proteins. When a venomous snake bites a person, the body’s immune system immediately reacts with inflammation and production of venom-specific antibodies. It takes precious time to make these antibodies, if it takes too long, the person may die.

Why are we injecting horses with snake venom?

Scientists determined that a horse can be injected with the venom or antigen, and the horse will have plenty of time to make the antibodies, which will be collected and purified long before a person is ever bitten by the snake. This is how we use another animal’s natural immune system to make anti-venom, sometimes called antivenin.

How does that differ from vaccines?

Vaccines work in a similar way, but the antigens are introduced into your own body weeks before the antibodies are needed.

So why can’t we create a vaccine against allergies?

Allergies are when you develop an immune response to a common antigen that isn’t pathogenic, like tree pollen. If we made a vaccine containing tree pollen antigen, it may actually cause allergies.

Similarly, autoimmune disorders are when your immune system targets the wrong antigen. Only in autoimmunity, the antigen is part of your own body.

Here you’ll see an immune cell working hard, chasing down a pathogen, to keep you healthy.

That diligent security-guard-cell isn’t fighting alone however. It is important to remember that your ability to avoid or fight disease is due to many different things. From the structure of your skin, to the behavior of washing your hands, to the community of healthy gut bacteria that are keeping pathogens at bay, your biology includes many pieces that play a role in keeping you healthy.