Low levels of HIV-1 envelope-mediated fusion are associated with long-term survival of an infected CCR5-/- patient.

Objectives: This study investigated whether Env-mediated fusion levels of R5X4 viruses are associated with long-term survival of an infected CCR5-/- patient.

Design: Four R5X4 Envs were cloned from each of two infected homosexual individuals (DR and C2) homozygous for the CCR5Δ32 allele. DR is a long-term survivor chronically infected with HIV-1 and his Envs were cloned 12 years after testing HIV-infected, whereas C2 Envs were isolated 1 year after primary infection.