Related Experiment Videos
Glycoprotein of human immunodeficiency virus type 1 synthesized in chronically infected Molt3 cells acquires
R Pal1, F di Marzo Veronese, B C Nair
1Advanced BioScience Laboratories, Inc., Kensington, Maryland 20895.
Abstract:
Diversity of oligosaccharide structures on the glycoprotein of HIV-1 was studied in individual clones of Molt3 cells chronically infected with HIV-1IIIB. A glycoprotein of molecular weight 140 kD (gp140) was found to be shed into the medium from one of these clones, which unlike normally processed gp120, contained significant proportions of endo H resistant oligosaccharides. Treatment of infected cells with the inhibitors of oligosaccharide trimming enzymes affected the glycosylation pattern as well as the secretion of the glycoprotein into the medium. The exposure of the principal neutralizing domain (PND) on the surface of gp140, as measured by its accessibility to thrombin cleavage, was comparable to that observed with gp120. Sera obtained from mice inoculated with purified gp140 contained high titered anti-V3 antibodies and blocked HIV-1IIIB-induced syncytium formation. These results demonstrate that although glycosylation of viral glycoproteins is governed by the host cell glycosyl transferases, glycoprotein secreted from biological clones of the same host cells acquires different oligosaccharide structures. Exposure and immunogenicity of the PND in one such glycosylation variant are comparable to the normally processed gp120 molecule.
Insights
HIV-1 glycoprotein (gp140) from infected cells showed diverse oligosaccharide structures, differing from typical gp120. This variant exposed a key neutralizing domain and elicited protective antibodies, suggesting altered glycosylation impacts HIV immunogenicity.
Area of Science:
- Virology
- Glycobiology
- Immunology
Background:
- Human Immunodeficiency Virus type 1 (HIV-1) glycoproteins are crucial for viral entry and are heavily glycosylated.
- Oligosaccharide structures on viral glycoproteins can influence their processing, stability, and immunogenicity.
- Understanding glycosylation patterns is vital for developing effective HIV-1 therapies and vaccines.
Purpose of the Study:
- To investigate the diversity of oligosaccharide structures on HIV-1 glycoprotein (gp140) shed from chronically infected Molt3 cell clones.
- To compare the exposure and immunogenicity of the principal neutralizing domain (PND) on gp140 with normally processed gp120.
- To assess the impact of glycosylation inhibitors on glycoprotein secretion and glycosylation patterns.
Main Methods:
- Analysis of oligosaccharide structures on shed gp140 from individual HIV-1 infected Molt3 cell clones.
- Treatment of infected cells with inhibitors of oligosaccharide trimming enzymes.
- Assessment of thrombin cleavage accessibility to measure PND exposure on gp140.
- Immunization of mice with purified gp140 and evaluation of anti-V3 antibody response and neutralization capacity.
Main Results:
- A gp140 variant with endo H resistant oligosaccharides was shed into the medium.
- Inhibitors of oligosaccharide trimming enzymes altered glycosylation and secretion of the glycoprotein.
- The PND on gp140 showed comparable exposure to that on gp120.
- Sera from mice immunized with gp140 contained high-titered anti-V3 antibodies and blocked syncytium formation.
Conclusions:
- Host cell glycosyl transferases govern viral glycoprotein glycosylation, but biological clones can acquire distinct oligosaccharide structures.
- The secreted gp140 variant exhibits comparable PND exposure and immunogenicity to the standard gp120 molecule.
- Altered glycosylation of HIV-1 glycoproteins can lead to variations in structure and immunogenicity, impacting potential therapeutic targets.