Jenner successfully used cowpox virus as a vaccine against the virus that causes smallpox. Why was he successful even though he used viruses of different kinds?
A)The immune system responds nonspecifically to antigens.
B)The cowpox virus made antibodies in response to the presence of smallpox.
C)Cowpox and smallpox are antibodies with similar immunizing properties.
D)There are some antigenic determinants common to both pox viruses.

Question

Quizplus · Accepted Answer

There are some antigenic determinants common to both pox viruses, which allowed the immune system to recognize and mount a response to the smallpox virus after being exposed to the cowpox virus. This cross-reactivity is the basis for the success of Jenner's vaccine.

Jenner Successfully Used Cowpox Virus as a Vaccine Against the Virus