Rapid complementation assays measuring replicative potential of human immunodeficiency virus type 1 envelope glycoprotein mutants

Abstract

Rapid assays which measure the ability of mutant human immunodeficiency virus type 1 envelope glycoproteins to mediate cell-free and/or cell-to-cell transmission of virus are described. By using these assays, envelope glycoprotein mutants with varying degrees of syncytium-forming ability were tested for ability to complement viral replication in trans. As expected, mutants that dramatically affect association of the gpl20-gp4l envelope subunits, CD4 binding, or membrane fusion were unable to form syncytia or to support cell-free or cell-to-cell transmission. Surprisingly, some membrane fusion-defective mutants significantly attenuated in syncytium-forming ability were able to complement viral replication. Conversely, mutations in the carboxyl terminus of gp4l transmembrane glycoprotein, although not affecting syncytium-forming ability, significantly attenuated both forms of virus transmission. These results indicate that syncytium formation is not sufficient for cell-to-cell transmission of human immunodeficiency virus type 1. Furthermore, virus transmission appears to be less sensitive to inhibition of membrane fusion than is syncytium formation.

Hypericum hircinumL. components as new single-molecule inhibitors of both HIV-1 reverse transcriptase-associated DNA polymerase and ribonuclease H activities

“…Therefore, we asked whether its antiviral effect could be ascribed to the inhibition of the early steps of the virus cycle. To this end, we used an env complementation assay that measures the efficiency of the early events in a single round of infection (Helseth et al, 1990). In this assay, an env-defective provirus encoding the bacterial chloramphenicol acetyltransferase gene was complemented in trans by the envelope glycoprotein derived from the laboratory-adapted T-cell-tropic strain HXBc2, which uses CXCR-4 as a coreceptor (Feng et al, 1996).…”

Enhancement of Infectivity of a Non‐Syncytium Inducing HIV‐1 by sCD4 and by Human Antibodies that Neutralize Syncytium Inducing HIV‐1

“…Envelope traus-complementution assuy. This assay was based on a previously described n««,v-complementation assay in which an envdefective HIV-l provirus, encoding the bacterial CAT reporter gene [15]. was complemented for a single round of replication by a set of recently described HIV-1 envelope glycoproteins [9].…”

Multiplex Evaluation of Influenza Neutralizing Antibodies with Potential Applicability to In-Field Serological Studies

“…In addition, for stability studies pCSLZW, expressing the lacZ gene [18], was used in conjunction with the clade 1 A/Vietnam/1194/2004 HA and exogenous bacterial NA (1 unit/mL; Sigma, UK) to produce lacZ pseudotype viruses, and infection of HEK 293T/17 cells was detected using the X-gal substrate as described by us previously [18]. Lentiviral pseudotypes bearing rabies CVS-11 [25] and HIV-1 [26] envelope glycoproteins were utilized for comparison.…”