Immune system modeling

Model notes: I matched antibody shapes to specific antigen shapes, like a lock and key. Only the complementary antibody bound the antigen; mismatched shapes did not stick. When an antibody bound the pathogen, it neutralized it (blocked it from infecting cells) and tagged it for destruction.

Primary vs secondary response: On the first exposure, antibody levels rose slowly and stayed low. On the second exposure, memory B cells made antibodies rise faster and reach a much higher level. That speed-up is why the second exposure rarely makes you sick and is exactly what a vaccine pre-trains.