Antigen

Antigen explained in an easy to understand way:

Imagine you're at a party, and suddenly, an unfamiliar person crashes the event and starts causing trouble. This scenario is similar to how an antigen functions in your body, as it acts like that unwanted guest who disrupts the harmony. Just as the party hosts would quickly recognize the intruder and work to restore peace, your immune system identifies the antigen as a foreign substance and mounts a response to protect your body from potential harm.