Last year scientists made the amazing discovery that a set of previously unseen channels connected the brain to our immune system; now, it appears we might also need to rethink the immune system's relationship with the testes, potentially explaining why some men are infertile and how some cancer vaccines fail to provide immunity.
Researchers from University of Virginia School of Medicine discovered a 'very small door' which allows the testes to expose some of its antigens to the immune system without letting it inside.
For the past four decades the testes have been regarded as having 'immune privilege', meaning they don't mount an immune response when introduced to materials the immune system considers foreign.
Together with the brain, eyes, and placenta, inflammation in these parts of the body would be seriously bad news, which could explain why they are all physically or chemically hidden from the white cells and antibodies which protect us from infection.
The science WAS settled.