Virus Isolation and Production

Abstract

HIV-1 was first isolated from a primary culture of cells recovered from a lymph node biopsy taken from a young homosexual man [1]. The culture conditions used were those classic for the long-term culture of T lymphocytes, namely, three-day stimulation with phytohemagglutinin and maintenance in Interleukin 2 (IL-2). No virus was recovered from comparable cultures of this patient’s peripheral blood lymphocytes. Subsequently, the frequent isolation of HIV-1 from primary cultures and cocultures of peripheral blood lymphocytes from patients with AIDS and pre-AIDS was reported [2,3]. Today, two systems, one based on the helper T lymphocyte and one based on the mononuclear phagocyte, are commonly used for HIV-1 isolation. Because cells of the mononuclear phagocyte series and helper T lymphocytes bear the CD4 molecule, an essential component of the virus receptor [4,5], they are major natural host cells for HIV-1 infection and replication. Although other kinds of cells such as fibroblasts [6], endothelial cells [7], glial cells [8], and enterochromaffin cells [9] have been suggested as potential HIV-1 host cells, the evidence that these kinds of cells represent major sites of virus replication and expression in vivo is limited. With respect to this discussion, these kinds of cells are not commonly considered sources of isolable HIV-1 and they are certainly suboptimal for HIV-1 propagation for most purposes because the magnitude of virus expression is considerably lower than that from the natural host cells. T lymphocytes and mononuclear phagocytes, then, usually serve as the source of virus from clinical specimens. They also often serve as target cells for HIV-1 infection when cocultured with patient material.