Researchers Develop a Novel Drug to Treat HIV Infection

Researchers develop a novel drug to treat HIV infection.  In an in vitro experiment, wild-type viral isolates are cultured with human CD4 T lymphocytes in the presence of the drug.  Microscopic evaluation of these cells reveals no cytopathic changes, and no intracellular viral particles can be detected.  Further analysis reveals that in the presence of the drug the virus attaches to the cellular membrane, but fusion of the viral and cell membranes does not occur.  Which of the following is the most likely target of this medication?

A) Viral integrase enzyme
B) Viral Nef gene product
C) Viral Tat gene product
D) T-cell antigen receptor-CD3 complex
E) T-cell chemokine receptor
F) T-cell CTLA4 (CD152)