title: Effect of immune activation on the dynamics of human immunodeficiency virus replication and on the distribution of viral quasispecies.
abstract: Virus replication in a human immunodeficiency virus (HIV)-infected individual, as determined by the steady-state level of plasma viremia, reflects a complex balance of viral and host factors. We have previously demonstrated that immunization of HIV-infected individuals with the common recall antigen, tetanus toxoid, disrupts this steady state, resulting in transient bursts of plasma viremia after immunization. The present study defines the viral genetic basis for the transient bursts in viremia after immune activation. Tetanus immunization was associated with dramatic and generally reversible shifts in the composition of plasma viral quasispecies. The viral bursts in most cases reflected a nonspecific increase in viral replication secondary to an expanded pool of susceptible CD4(+) T cells. An exception to this was in a patient who harbored viruses of differing tropisms (syncytium inducing and non-syncytium inducing [NSI]). In this situation, immunization appeared to select for the replication of NSI viruses. In one of three patients, the data suggested that immune activation resulted in the appearance in plasma of virus induced from latently infected cells. These findings illustrate certain mechanisms whereby antigenic stimulation may influence the dynamics of HIV replication, including the relative expression of different viral variants.
authors.affiliation: Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA. mostrowski@nih.gov
authors.forename: M A
authors.initials: MA
authors.lastname: Ostrowski
authors.forename: D C
authors.initials: DC
authors.lastname: Krakauer
authors.forename: Y
authors.initials: Y
authors.lastname: Li
authors.forename: S J
authors.initials: SJ
authors.lastname: Justement
authors.forename: G
authors.initials: G
authors.lastname: Learn
authors.forename: L A
authors.initials: LA
authors.lastname: Ehler
authors.forename: S K
authors.initials: SK
authors.lastname: Stanley
authors.forename: M
authors.initials: M
authors.lastname: Nowak
authors.forename: A S
authors.initials: AS
authors.lastname: Fauci
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000821:virology; D017931:DNA Primers; D006678:HIV / Q000502:physiology*; D015658:HIV Infections / Q000276:immunology* / Q000821:virology*; D006801:Humans; D007156:Immunologic Memory; D008969:Molecular Sequence Data; D010802:Phylogeny; D013045:Species Specificity; D014779:Virus Replication / Q000276:immunology*
chemical_list: D017931:DNA Primers