Suppose an individual develops antibodies in response to a streptococcal pharyngitis infection. This is an example of

• A. active immunity
• B. passive immunity
• C. adoptive immunity
• D. immunoprophylaxis

Answer: (C)

The main concept is how the immune system generates its own antibody response to a pathogen. When someone has streptococcal pharyngitis, the body recognizes the bacteria and actively produces specific antibodies, along with memory cells. This is active immunity: the host's immune system is stimulated by the infection and creates lasting protection through its own response.

This differs from passive immunity, where antibodies come from an external source (like maternal antibodies or immune globulin) and provide only temporary protection without the body producing memory. Adoptive immunity involves transferring immune components or cells from a donor to another individual, not the person’s own response to infection. Immunoprophylaxis refers to preventive measures such as vaccines or preventive antibody administration before exposure. So, the situation shows active immunity.