The human immune system doesn't need to "interact" with a physical particle. White cells envelope (standard attack) a foreign particle, then dies around them, a

The human immune system doesn't need to "interact" with a physical particle. White cells envelope (standard attack) a foreign particle, then dies around them, and the resulting envelope is expelled. Your body is mostly fluid. Internal fluids don't really need complex chemical interactions but the dead white blood cell acts as an effective envelope for transport, by design. eg mucus in your nose when you're sick.