Can an antigen trigger an immune response?

An antigen is a substance that the immune system recognizes as foreign or dangerous, potentially triggering an immune response. When an antigen enters the body, it can provoke the adaptive immune system to produce specific antibodies aimed at neutralizing or eliminating the pathogen associated with that antigen. This process is vital for protecting the body against infections and diseases.

The ability of antigens to instigate an immune response is fundamental to understanding how vaccines work. Vaccines contain weakened or inactivated parts of a particular organism (antigens), which stimulates the immune system to respond without causing the disease, thus preparing the body for future encounters with the actual pathogen.

The notion that antigens can only trigger an immune response under certain conditions, or that this is limited to infants, does not encapsulate the broad and essential role of antigens in the immune system across all age groups and scenarios.