Can medications, antibiotics, surgery, etc. be considered part of our immune system? I realize this is actually more of a philisophical than a scientific question, but I was just wondering.
We may not make it inside our own bodies, but it fights disease, and humans (presumably) make it, although often not the same human who recieves it.
Any insights, y’all?
I demand insights!
Nope.
Immunizations (catch the root word there?) will boost, stimulate, activate our immune response. Those other modalities would be considered interventions from outside the body.
If you accept a metaphysical answer to a question about a physical, then sure, it’s part of your body’s immune system every bit as much as grandpa’s dentures are his real teeth.
If I strictly focused on the question alone my answer is absolutely no. If a human makes a drug and treats a dog is that drug then part of the dog’s immune system?
I think surgery would be right out. A drug that assists or modifies the body’s own immune system could be be in a gray area as you qualified the question.
Here’s one of those nice gray areas 
Most immunizations are a simulation of what often happens in nature. That’s how the immune system works, by response to stimulous. If it were sealed against “interventions from outside” the immune system would be moot.
This is, of course, all semantics, but referring to this type of stuff as part of the immune system would cause all kinds of confusion. For instance, drug manufacturers have to worry about a chemical’s effect on the immune system. If they just announced that this drug was PART of the immune system, well, you can see why we like to have definitions attached to words.