: if our immune system become stronger every time we encounter a virus/bacteria/ect when we are young, why does it become weaker when we are old instead of continuing to improve?
In: Biology
T cells and B cells are very important immune system components involved in fighting infections and forming lasting immunity. T cells are made in the thymus, which regresses with age and becomes a useless clump of fat cells by age 65. B cells develop in the bone marrow, which also loses function as you age.
So you lose the ability to make important immune system components with age.
your immune system doesn’t really get better as you age, it just gets a wider skillset and develops new tools to fight infections in the form of anti-bodies and whatnot. You can put a better rifle in someone’s hands, but it wont do them a lot of good if their hands are shaky. the immune system does still get weaker with advanced age, like the rest of the body.