Based on What You Know About Resistance to Infection, Why

Question

Based on what you know about resistance to infection, why are some people resistant to HIV?
A) They have a strong immune system that clears the virus completely.
B) They have been immunized in an experimental program.
C) They can't be infected with HIV even when exposed.
D) They never engage in risky behavior and thus can't become infected.

Accepted Answer

Some individuals possess a genetic mutation in the CCR5 receptor on their white blood cells, which prevents HIV from entering these cells, rendering them naturally resistant to HIV infection even when exposed.