Which describes the properties of a toxoid?

• A. Both pathogenic and immunogenic
• B. Pathogenic but not immunogenic
• C. Not pathogenic but immunogenic
• D. Neither pathogenic nor immunogenic

Answer: (C)

A toxoid is an inactivated toxin that can no longer cause disease but still triggers an immune response. The toxin is treated to destroy its harmful activity while keeping its protein structure recognizable to the immune system. This lets the body produce neutralizing antibodies that canblock the real toxin if encountered later. That’s why the correct description is not pathogenic but immunogenic. In vaccines like diphtheria and tetanus, the goal is to expose the immune system to the toxin’s antigenic parts without risking illness, so immunity can develop without any disease-causing effect.