Edward Jenner was able to demonstrate the first example of immunological cross-protection because
A) the smallpox virus was nonpathogenic.
B) the cowpox virus only affected milkmaids.
C) cowpox and smallpox viruses were metabolically different.
D) cowpox virus was structurally similar to the smallpox virus.
E) plague survivors were immune to smallpox.

Question

Quizplus · Accepted Answer

Edward Jenner discovered that the cowpox virus, which caused a much milder disease than smallpox, conferred immunity to smallpox because it was structurally similar to the smallpox virus. This similarity allowed the immune system to recognize and fight off smallpox after being exposed to cowpox.

Edward Jenner Was Able to Demonstrate the First Example of Immunological