Biology Regents Practice Exam

A potential malaria vaccine would most likely contain a weakened form of the malaria-causing organism. This approach leverages the principles of vaccination, where an attenuated (weakened) pathogen stimulates the immune system to recognize and remember the specific antigens associated with that pathogen. By introducing a weakened version of the malaria-causing organism into the body, the immune system can develop a robust response, producing antibodies and memory cells that can protect against future infections by the actual parasite.

Vaccination strategies often use weakened, killed, or subunit forms of pathogens to ensure that the body is prepared to attack the real pathogen if it enters the system later. This is why many effective vaccines rely on a strategy that closely resembles the natural infection, allowing the immune system to learn without causing disease.

Other choices involve mechanisms that are not typically the basis for vaccine design. Weakened drugs would not generate an immune response. White blood cells from infected individuals would not provide the necessary immunological memory for the recipient. Antibodies alone could offer temporary immunity but would not provide the longer-lasting protective effect associated with vaccines that train the immune system.