: 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?

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: 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

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.

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.