title: Nef alleles from human immunodeficiency virus type 1-infected long-term-nonprogressor hemophiliacs with or without late disease progression are defective in enhancing virus replication and CD4 down-regulation.
abstract: Infection with human immunodeficiency virus (HIV)-encoding defective nef variants may contribute to a relatively benign course of disease in a minority of long-term nonprogressors (LTNP). We have examined the functions of nef alleles from six individuals belonging to the same cohort of hemophiliacs infected with HIV-1 prior to 1985 and classified as LTNP in 1995. Three out of six individuals have progressed to HIV disease (late progressors [LP]), whereas the three remainders have maintained their LTNP status at least up to 2003. The nef alleles were obtained from both plasma virus and peripheral blood mononuclear cells of all six individuals in 1995 and 1998. The proportion of sequences containing mutations not yielding Nef expression significantly diminished in 1998 versus that in 1995. Several previously defined functional regions of intact nef alleles were highly conserved. However, the major variant obtained in 1998 from plasma RNA of five out of six individuals significantly reduced HIV infectivity/replication and impaired Nef-mediated CD4 but not major histocompatibility complex class I antigen down-modulation from the cell surface. Thus, functional alterations of the nef gene are present in both LP and LTNP, suggesting that Nef defectiveness in vitro is not necessarily associated with the long-term maintenance of LTNP status. Of interest is the fact that isolates from three out of three LP showed a dual CCR5/CXCR4 coreceptor use (R5X4), in contrast to those from LTNP, which were exclusively R5. Thus, in vivo evolution of gp120 Env to CXCR4 use appears to be associated with HIV disease progression in individuals infected with nef-defective viruses.
authors.affiliation: AIDS Immunopathogenesis Unit, San Raffaele Scientific Institute, Milan, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Crotti
authors.forename: Francesca
authors.initials: F
authors.lastname: Neri
authors.forename: Davide
authors.initials: D
authors.lastname: Corti
authors.forename: Silvia
authors.initials: S
authors.lastname: Ghezzi
authors.forename: Silvia
authors.initials: S
authors.lastname: Heltai
authors.forename: Andreas
authors.initials: A
authors.lastname: Baur
authors.forename: Guido
authors.initials: G
authors.lastname: Poli
authors.forename: Elena
authors.initials: E
authors.lastname: Santagostino
authors.forename: Elisa
authors.initials: E
authors.lastname: Vicenzi
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D015704:CD4 Antigens / Q000378:metabolism; D002460:Cell Line; D015331:Cohort Studies; D004279:DNA, Viral / Q000235:genetics; D003673:Defective Viruses / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology; D015536:Down-Regulation; D005500:Follow-Up Studies; D015754:Genes, nef; D015699:HIV Envelope Protein gp120 / Q000235:genetics; D015658:HIV Infections / Q000150:complications* / Q000276:immunology / Q000821:virology*; D020276:HIV Long-Term Survivors; D015497:HIV-1 / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity / Q000502:physiology; D006467:Hemophilia A / Q000150:complications*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics; D019713:Receptors, CCR5 / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014779:Virus Replication / Q000235:genetics
chemical_list: D015704:CD4 Antigens; D004279:DNA, Viral; D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments; D019713:Receptors, CCR5; D019718:Receptors, CXCR4