All 4 Uses of

immune
in
The Magic Mountain

And this was how the old man was viewed, both during his lifetime and after, by his fellow citizens; and even though little Hans Castorp understood nothing about the affairs of government, the perceptions gained by his own calm, alert child's eye were much the same—unspoken and therefore uncritical perceptions, though enthusiastic for all that, which when they later became conscious memories retained their exclusively positive stamp, immune to all discussion or analysis.†
Chpt 2.1

immune = not in danger of suffering from something OR relating to disease resistance

The answer people gave was: Life, a special immunity of living protoplasm—and acted as if they did not notice what a mystical explanation that was.†
Chpt 5.7 *

immunity = the state of not being in danger of suffering from something

After that, a person would be immune to the effects of any climate anywhere, could stand firm against every onslaught—provided, of course, he waited for healing to take hold completely, and so forth.†
Chpt 6.1

immune = not in danger of suffering from something OR relating to disease resistance

James Tienappel had mentioned all these matters during their carriage ride, of course, but the topics had fallen away, as good as dead, as if they had bounced off Hans Castorp's calm, resolute, and genuine indifference, which acted as a kind of immunity that kept anything from touching him, just as he was insensitive to the chill of the autumn evening and could reply, "We're never cold."†
Chpt 6.5

immunity = the state of not being in danger of suffering from something

Definition:

not in danger of being affected by something -- especially a disease

or:

relating to disease resistance