In the Late 1990s, a Group of Individuals Was Discovered

Multiple Choice

In the late 1990s, a group of individuals was discovered that remained uninfected with HIV, in spite of multiple exposures to the virus. Analysis indicated that these HIV-resistant individuals had a homozygous deficiency caused by a 32-bp deletion in a single gene, and furthermore, that this mutation was present at a frequency of ~10% (in heterozygous form) in individuals of European descent. These data provided clear evidence indicating that:

A) Healthy individuals can have a genetic deficiency in the expression of CD4.
B) Testing for HIV by seroconversion does not identify all infected individuals.
C) HIV infection requires a co-receptor in addition to CD4.
D) Some individuals can be infected with HIV but not develop AIDS.
E) Both R5 and X4 variants of HIV are equally important in HIV transmission.