A 36-Year-Old Man with a History of a Positive Anti-HIV

A 36-year-old man with a history of a positive anti-HIV antibody test comes to the clinic with fever, sore throat, nonproductive cough, and weight loss. This patient has had a partner for 8 years with whom he has frequently engaged in unprotected sexual intercourse. The partner is a healthy 29-year-old man who is HIV negative. The partner's relative "resistance" to HIV infection may be due to a loss-of-function mutation in which of the following proteins?

A) CD4
B) CD8
C) CCR5
D) Tumor necrosis factor (TNF)
E) NF-ĸB