A molecular clone of simian-human immunodeficiency virus (Delta vpuSHIV(KU-1bMC33)) with a truncated, non-membrane-bound vpu results in rapid CD4(+) T cell loss and neuro-AIDS in pig-tailed macaques

We report on the role of vpu in the pathogenesis of a molecularly cloned si mian-human immunodeficiency virus (SHIVKU-1bMC33), in which the lat, rev, v pu, env, and nef genes derived from the uncloned SHIVKU-1b virus were inser ted into the genetic background of parental nonpathogenic SHIV-4. A mutant was constructed (Delta vpuSHIV(KU-1bMC33)) in which 42 of 82 amino acids of Vpu were deleted. Phase partitioning studies revealed that the truncated V pu was not an integral membrane protein, and pulse-chase culture studies re vealed that cells inoculated with Delta vpuSHIV(KU-1bMC33) released viral p 27 into the culture medium with slightly reduced kinetics compared with cul tures inoculated with SHIVKU-1bMC33. Inoculation of Delta vpuSHIV(KU-1bMC33 ) into two pig-tailed macaques resulted in a severe decline of CD4(+) T cel ls and neurological disease in one macaque and a more moderate decline of C D4(+) T cells in the other macaque. These results indicate that a membrane- bound Vpu is not required for the CD4(+) T cell loss and neurological disea se in SHIV-inoculated pig-tailed macaques. Furthermore, because the amino a cid substitutions in the Tat and Rev were identical to those previously rep orted for the nonpathogenic SHIVPPc, our results indicate that amino acid s ubstitutions in the Env and/or Nef were responsible for the observed CD4+ T cell loss and neurological disease after inoculation with this molecular c lone. (C) 2000 Academic Press.