Characteristics of primary infection of a European human immunodeficiency virus type 1 clade B isolate in chimpanzees

The aim of the study was to select, from a panel of candidate European human immunodeficiency virus type 1 (HIV-1) clade B primary virus isolates, one isolate based on replication properties in chimpanzee peripheral blood mononuclear cells (PBMC). Secondly, to evaluate the in vivo kinetics of primary infection of the selected isolate at two different doses in two mature, outbred chimpanzees (Pan troglodytes). Four different low passage, human PBMC-cultured 'primary' HIV-1 isolates with European clade B consensus sequence were compared for their ability to replicate in vitro in chimpanzee versus human PBMC. The isolate which yielded the highest titre and most vigorous cytopathic effect in chimpanzee PBMC was evaluated for coreceptor usage and chosen for evaluation in vivo. Only the HIV-1Han2 isolate replicated in chimpanzee PBMC in vitro at detectable levels. This isolate was demonstrated to utilize CCR4, CCR5 and CXCR4 coreceptors and could be inhibited by beta-chemokines. Infection of chimpanzees was demonstrated by viral RNA and DNA PCR analysis, both in plasma as well as in PBMC and lymph node cells as early as 3 weeks after inoculation. Antibodies developed within 6 weeks and continued to increase to a maximum titre of approximately 12800, thereafter remaining in this range over the follow-up period of 2 years. Compared to cell line-adapted HIV-1 isolates there were slight but no dramatic differences in the kinetics of infection of chimpanzees with this particular primary isolate.

Search for proviral simian sarcoma associated virus sequences in bone marrow cells from children with neoplasms of mesenchymal origin

DNAs obtained from bone marrow cells of 31 children with neoplasms of mesenchymal origin were tested for the presence of proviral simian sarcoma associated virus by southern blot-hybridization. The lower limit of detection in this method was one provirus per 20-30 cells. Applying stringent conditions of hybridization, no proviral DNA could be detected in any of the samples tested, most of which were from children with leukemia or with bone marrow invading lymphosarcomas. Relaxed conditions of hybridization revealed a diffuse pattern of hybridizing fragments which was similar in all DNAs tested, including normal human DNA.