What is the role of antigens in the immune response?

Antigens play a crucial role in the immune response by being molecules or structures that are recognized by the immune system as foreign. They are typically found on the surface of pathogens, such as bacteria, viruses, and other microorganisms. This characteristic allows antigens to trigger an immune response, leading to the activation of immune cells that target and eliminate the pathogen.

When the immune system detects these foreign antigens, it responds by initiating a variety of mechanisms that include the activation of T-cells and the production of antibodies by B-cells. By identifying and binding to these antigens, the immune system can effectively recognize and respond to infections, thus protecting the body from diseases.

The other options do not accurately describe the primary role of antigens in the immune response. While antigens do indeed activate T-cells, they are not themselves produced by lymphocytes—rather, lymphocytes recognize and respond to antigens. Furthermore, antigens do not directly destroy bacteria; instead, they serve as signals that prompt other immune components to act against the pathogens.