The second hit hypothesis suggests the immune system learned to recognize foreign tissue and became more effective at eliminating it.

“exactly so it was kind of the second exactly it's the same principle so this is kind of the second hit hypothesis that the body the immune system learned to recognize this foreign tissue and and the immune system was even more effective in eliminating it”

“if you took a second skin graft from that same individual and put it on it died faster it's as if the body was primed to to destroy that new skin graft kind of sounds like a vaccine huh”