Pseudotypes of human T-cell leukemia virus types 1 and 2: neutralization by patients' sera.

Abstract

Pseudotypes of vesicular stomatitis virus (VSV) bearing envelope antigens of human T-cell leukemia virus (HTLV) types 1 and 2 were prepared by propagating VSV in cells lines productively infected with HTLV. Plaque assays of VSV(HTLV) pseudotypes were employed to determine the presence of (i) HTLV receptors on cells and (it) neutralizing antibodies in the serum of patients with adult T-cell leukemialymphoma (ATLL). Cell surface receptors for HTLV-1 and HTLV-2 were found on nonlymphoid cells of human and mammalian origin. Neutralizing antibodies specific to VSV(HTLV-1) were found in sera of ATLL patients in titers varying from 1:50 to 1:30,000 and did not correlate closely with antibody titers for internal viral antigens. Sera from ATLL patients in the United Kingdom (Caribbean immigrants), United States, and Japan completely neutralized VSV(HTLV-1), indicating that the HTLV isolates from these distinct geographic regions represent a single envelope serotype. Neutralization of VSV(HTLV-1) was more specific and more sensitive than assays of syncytium inhibition. No crossneutralization was observed between bovine leukosis virus and HTLV, and only limited cross-reaction was found for envelope antigens of HTLV-1 and HTLV-2. These studies show that VSV(HTLV) pseudotypes can be readily used to screen for neutralizing antibodies in patients' sera and to distinguish HTLV envelope serotypes.Human T-cell leukemia virus type 1 (HTLV-1) is a C-type retrovirus associated with certain malignancies of mature T cells known as adult T-cell leukemia-lymphoma (ATLL) (1, 2). The first isolates of HTLV were made from tumor cells of American patients (3,4). A virus formerly known as adult Tcell leukemia virus (ATLV) (5, 6), endemic in the regions of southwestern Japan where ATLL is prevalent (1,7,8) (19,20). We have adopted the VSV system for HTLV studies.When cells chronically infected with retroviruses are superinfected with VSV, a proportion of the progeny VSV particles bear the envelope glycoproteins of the retrovirus (20)(21)(22). Core antigens of the retrovirus are not assembled into VS virions. The VSV pseudotypes resist neutralization by anti-VSV antibodies but are sensitive to neutralizing antibodies specific to the retrovirus donating the envelope antigens. The host range for viral penetration of pseudotypes is restricted to cells bearing receptors for the retrovirus. Following penetration and uncoating, however, the VSV genome contained in the pseudotype particle replicates to produce nonpseudotype progeny. Thus, a cytopathic plaque assay of VSV pseudotypes can be used to determine receptor expression, receptor interference, and neutralizing antibodies specific to the retrovirus encoding the envelope glycoproteins.

Infection of human endothelial cells by human T-cell leukemia virus type I.

“…In recent reports, pseudotypes of vesicular stomatitis virus bearing HTLV-I envelope antigens were shown to be capable of penetrating a variety of mammalian cell types, indicating that putative receptors for HTLV-I are common (24). Similar results have been shown by immunofluorescence detection of the binding of this virus to several types of lymphoid and non-lymphoid cells (39).…”

“…In vitro, additional hematopoietic cell types have been shown to be susceptible to HTLV-I infection and transformation, including normal suppressor/cytotoxic (OKT8 positive) T lymphocytes as well as certain non-T-bone marrow cells (22,23). Moreover, viral pseudotypes bearing HTLV-I or HTLV-II envelope glycoproteins can penetrate a variety of mammalian cell lines (24). In several of these susceptible cells, syncytia were induced by cocultivation with HTLV-I-producing cells (25,26) and in a single human osteosarcoma cell line stable HTLV-I replication could be demonstrated (27).…”

HTLV-1 tropism and envelope receptor

“…It was rapidly shown by Env interference to superinfection that HTLV-1 and -2 (Clapham et al, 1984) and related simian isolates (Sommerfelt and Weiss, 1990) share the same receptor. However, the search for a receptor was hampered by the combination of (i) a widely expressed receptor among vertebrate cell lines, (ii) an Env-mediated rampant syncytial effect and (iii) an inability to produce high titering cell-free virions.…”

“…Receptor detection assays Three main categories of read-outs have been used exclusively or in combination to evaluate the availability of functional HTLV receptors: (i) Infection with heterologous nonretroviral (Clapham et al, 1984;Sommerfelt et al, 1988;Sommerfelt and Weiss, 1990) or retroviral (Sutton and Littman, 1996;Trejo and Ratner, 2000;Manel et al, 2003a) virions pseudotyped with HTLV-1 Env. An adaptation of this assay consists of the substitution of the HTLV-1 env gene for that of the VSV-G transmembrane protein into the VSV genome (Okuma et al, 2003).…”

Human T cell lymphotropic virus type I genomic expression and impact on intracellular signaling pathways during neurodegenerative disease and leukemia

“…In vitro infection is usually initiated by cocultivation of gamma-irradiated HTLV-I producing cells with target cells, although the infection efficiency is quite low compared to other retroviruses such as HIV-1. Viral attachment and entry into susceptible cells requires a specific cell surface receptor which has not yet been identified but is present on numerous cells, including those of non-human origin (37,38). Although the majority of cells infected by HTLV-I in vivo are CD4 + cells, the CD4 surface molecule has been demonstrated not to be the receptor for HTLV-I (39,40).…”