title: Virus-free survival and down-regulation of CD4 in C8166 cells infected with human immunodeficiency virus type 1 at low density.
abstract: Compared with other T cell lines, C8166 lymphocytes are particularly susceptible to human immunodeficiency virus (HIV) infection and the outcome is invariably cell death. The results reported in this study demonstrate that the virus-induced cytolysis is strongly dependent on the initial cell density of C8166 cultures. Cultures diluted to 50 to 500 cells/ml almost completely maintained their cell duplication rate and released infectious virus into the medium. HIV infection of diluted C8166 cells is a simple and easily reproducible procedure for obtaining persistently infected cultures. These cultures contained genomic and extragenomic HIV DNA, the latter being assayed by PCR for two-long terminal repeat circular forms. The status of persistent infection disappeared within 2 months. The recovery is due to the replacement of CD4 down-regulated infected cells by overgrowing uninfected cell variants, which are transcriptionally inactive for CD4. The mechanisms underlying the emergence of these variants in persistently infected cultures are considered.
authors.affiliation: Centre of Virology, S. Camillo Hospital, USL RM 10, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Benedetto
authors.forename: A R
authors.initials: AR
authors.lastname: Garbuglia
authors.forename: A
authors.initials: A
authors.lastname: Di Caro
authors.forename: E
authors.initials: E
authors.lastname: Lo Presti
authors.forename: E
authors.initials: E
authors.lastname: Alfani
authors.forename: C
authors.initials: C
authors.lastname: Delfini
mesh_terms: D015704:CD4 Antigens / Q000096:biosynthesis*; D002455:Cell Division; D002460:Cell Line; D002470:Cell Survival; D004279:DNA, Viral; D015536:Down-Regulation; D015497:HIV-1 / Q000235:genetics / Q000254:growth & development* / Q000276:immunology; D006801:Humans; D013601:T-Lymphocytes / Q000276:immunology / Q000382:microbiology*; D016662:Virus Integration
chemical_list: D015704:CD4 Antigens; D004279:DNA, Viral