When a person is exposed to an infectious disease for a second time, which type of substance will be released during the immune response mechanism?

When a person is exposed to an infectious disease for the second time, the immune system reacts by releasing antibodies. These are proteins produced by B cells that specifically target and neutralize pathogens such as viruses and bacteria. During the first encounter with an infectious agent, the immune system generates a primary response, which includes the development of memory B cells that will recognize the pathogen if it appears again. Upon re-exposure, the pre-existing memory cells rapidly produce antibodies tailored to the specific invader, leading to a quicker and more effective immune response. This mechanism is fundamental to how vaccines work, as they prepare the immune system to recognize and combat pathogens without the person experiencing the disease.

In contrast, antigens are substances on the surface of pathogens that trigger an immune response, but they are not released by the body. Antitoxins are specifically produced to neutralize toxins but are not the focus in the context of an infectious disease. Toxins, which are harmful substances produced by certain bacteria, are also unrelated to the context of the body’s protective immune response during a subsequent infection.