Final answer:
When an antibody binds to an antigen and a normal PrP turns into a pathogenic prion, both undergo a conformational change or misfolding.
Step-by-step explanation:
When an antibody binds to an antigen and when a normal PrP is converted into a pathogenic prion, both undergo a process called conversion or misfolding.
In the case of antibodies and antigens, the antibody recognizes and binds to the specific antigen, which results in a change in the conformation of the antibody. This conformational change is necessary for the antibody to exert its function, such as neutralizing the antigen or marking it for destruction by other immune cells.
Similarly, in the case of prions, the normal cellular form of the prion protein (PrPC) is converted into the disease-causing form (PrPSC) through a conformational change. This misfolding of PrPC into PrPSC leads to the accumulation of abnormal prion proteins, which can cause neurodegenerative diseases.