In vitro characterization of HIV type 1 biological clones from asymptomatic and symptomatic pediatric patients.
To investigate the mechanisms of HIV-1 cytopathogenicity, functional biological HIV-1 clones were isolated from two infected children with high viral loads in vivo. Clone HC4 was isolated from a symptomatic child and clone GC6 8-4 was isolated from an asymptomatic child. These clones were characterized for their ability to induce syncytia, and to replicate and induce single-cell death in peripheral blood-derived normal CD4 T cell cultures containing anti-CD4 antibody. Despite similar viral loads as determined by p24 antigen production or viral RNA expression, GC6 8-4 was noncytopathogenic and HC4 was cytopathogenic. Since we had demonstrated that mitochondrial dysfunction correlated with HIV-1-induced cell death, we determined whether the cytopathogenic HC4 clone decreased mitochondrial viability using a mitochondrial-specific dye, rhodamine-123. Following infection, mitochondrial viability decreased in cells infected with HC4 by day 4 and continued to decline through day 7 when compared to uninfected cells. By day 7 postinfection, greater than 80% of the cells in culture were dead. Similar analyses on CD4 T cells infected with the noncytopathogenic GC6 8-4 demonstrated that mitochondria remained functionally viable and > 90% of the cells excluded trypan blue. These studies describe a cell culture system to study single-cell death in the absence of syncytia and secondary infection. Results with two patient-derived HIV-1 biological clones suggest that loss of mitochondrial viability may play a role in HIV-1-induced cytopathogenicity.
Forte
S E
SE
Department of Pediatrics, University of Massachusetts Medical Center, Worcester 01605, USA.
Sullivan
J L
JL
Somasundaran
M
M
D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D002460:Cell Line; D002478:Cells, Cultured; D002675:Child, Preschool; D003588:Cytopathogenic Effect, Viral; D015726:Giant Cells; D006679:HIV Seropositivity / Q000276:immunology / Q000821:virology*; D015497:HIV-1 / Q000235:genetics / Q000276:immunology / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D007963:Leukocytes, Mononuclear; D008928:Mitochondria / Q000502:physiology; D010641:Phenotype