Hepatitis B virus produced by transfected Hep G2 cells causes hepatitis in chimpanzees.

Abstract

We have reported that clonal cells derived from Hep G2 cells transfected with a plasmid containing hepatitis B virus (HBV) DNA secrete spherical and filamentous forms of hepatitis B surface antigen (HBsAg), core particles, and virions into the culture medium. Here we describe the development of typical hepatitis in two chimpanzees following intravenous inoculation with the medium in which the transfected cells had grown. The liver biopsies from these animals showed characteristic lesions in parenchyma and portal tracts, more conspicuous at an earlier time in the chimpanzee that had received a greater number of virions. The amount of HBsAg in the serum of one infected chimpanzee increased with time after the initial inoculation and then decreased concomitantly with the appearance of antibodies against HBsAg and core antigens. HBsAg remained detectable in the other animal throughout the course of the experiment.The levels of hepatitis B "e" antigen in both animals peaked at week 5, signifying the acute phase of the infection. The activities of serum enzymes that are markers for necroinflammation also increased. The hepatitis HBsAg subtype of the virions isolated from the patient whose DNA was cloned and then used for transfection of the Hep G2 cells was the same as that found in the chimpanzees. Furthermore, the restriction enzyme analysis of the viral DNA isolated from the chimpanzees was identical to the cloned DNA. Thus, HBV DNAtransfected Hep G2 cells can support the replication of virions that, in turn, produce hepatitis in chimpanzees.The lack of a tissue culture system in which hepatitis B virus (HBV) replicates has long impeded the study of the replicative cycle and the oncogenic potential of the virus. Recently, we (1)

Molecular and Cellular Biology

“…In the absence of tissue culture infection this approach is widely used to study the viral life cycle (1,36,44). Under these conditions, by primer extension analysis we revealed a novel transcription initiation site next to the P(A)S-TATA box.…”

Molecular Virology of Hepatitis B Virus for Clinicians

“…In contrast, infection of tissue culture lines of transformed liver cancer cells as well as primary human and chimpanzee hepatocytes, maintained as monolayers in culture dishes, with HBV is extremely inefficient and particularly difficult [16]. The reasons for this striking discrepancy in vivo and in vitro are not known and especially puzzling since HBV DNA introduced into cultured cells can result in production of infectious virus [17,18]. One possibility is that hepatocytes and malignantly transformed cells, explanted from the organ and grown in tissue culture, lose properties essential to the early steps in the virus life cycle such as receptors and or co-receptors.…”

“…For example, transfection of plasmids containing infection competent HBV genomes into human hepatoma Huh7 and hepatoblastoma HepG2 cultures results in production and secretion of enveloped virions [17,19]. These systems allow for the study of HBV RNA transcription, DNA synthesis, and the assembly and secretion of viral particles which occur following transfection, but the early events of virus infection of cells such as receptor binding, entry, capsid disassembly and the first-round cccDNA formation can not be studied.…”

Caffeoyl pyrrolidine derivative LY52 inhibits hepatocellular carcinoma invasion via suppressing matrix metalloproteinase-2

“…1), white powder, insoluble in water, was designed and synthesized as described previously [12]. [15,16]. HepG2 cells were cultured in DMEM containing 10% heatinactivated fetal bovine serum (FBS), and HepG2.2.15 cells in RPMI 1640 containing 10% heat-inactivated FBS supplemented with penicillin (100 units/ml), streptomycin (100 lg/ml), 2 mM glutamine and sodium bicarbonate (2.2 g/l) at 37°C in a humid 5% CO 2 -air atmosphere.…”