Our adaptive immunity, the body identifies a threat, and we create antibodies specifically designed to that threat. The threat is neutralized, and the adaptive immune system "remembers" it, so hopefully future responses to the same threat are also neutralized.
We often hear people talk about "strengthening our immune system". There is a truly obscene amount of supplements that claim to do that.
What we really need is a balanced quad services covid cleaning immune system. When out of balance, the immune system not only fails to protect us, but it can even turn against us, mistaking our own cells for invading pathogens (nasties), resulting in debilitating chronic inflammation and autoimmune diseases. Lupus, rheumatoid arthritis, allergies are all examples of autoimmune responses.