Certified Nursing Assistant (CNA) Practice Exam

The immune system develops specialized proteins called what, which help the body fight off certain microbes?

1. Antibiotics

2. Antibodies

3. Antigens

4. Antitoxins

The correct answer is: Antibodies

The correct answer is antibodies. Antibodies are specialized proteins produced by the immune system in response to the presence of foreign substances known as antigens, which can include bacteria, viruses, and other pathogens. Each antibody is specific to a particular antigen, allowing the immune system to effectively identify and neutralize these invaders. Antibiotics, on the other hand, are medications used to kill or inhibit the growth of bacteria and are not proteins produced by the immune system. Antigens are molecules found on the surface of pathogens that trigger an immune response, but they are not the proteins that fight microbes. Antitoxins are specific antibodies produced to neutralize toxins, rather than directly fighting off a wide range of microbes. Thus, antibodies are the key proteins that enable the immune system to recognize and eliminate harmful pathogens.