Antibodies are produced by the humoral arm of the immune system, but there is another arm: https://en.wikipedia.org/wiki/Cell-mediated_immunity https://en.wiki

Antibodies are produced by the humoral arm of the immune system, but there is another arm: https://en.wikipedia.org/wiki/Cell-mediated_immunity https://en.wikipedia.org/wiki/Cell-mediated_immunity Basically this other arm tells infected cells to kill themselves, and they comply.