What is the term for a procedure that involves the administration of a substance to stimulate the immune response?

The term that describes a procedure involving the administration of a substance to stimulate the immune response is immunization. This process typically includes the application of vaccines, which contain antigens that provoke the body's immune system to produce a defense against specific pathogens, such as viruses or bacteria.

Immunization serves to educate the immune system, enabling it to recognize and respond more effectively if exposed to the actual disease-causing organisms in the future. By introducing a harmless form of the pathogen or a piece of it (like proteins or sugars), the immune system can build memory cells for quick response upon re-exposure.

The other terms have distinct meanings that do not pertain to the specific act of stimulating immunity. Diagnosis refers to the identification of a disease based on symptoms and tests, therapy involves treatment to alleviate symptoms or manage diseases, and prophylaxis usually involves measures taken to prevent disease, which may include immunization but does not specifically denote the act of stimulating the immune response through administration of a substance.