Gp120 stability on HIV-1 virions and Gag-Env pseudovirions is enhanced by an uncleaved Gag core

• Published in: Virology (New York, N.Y.) Vol. 314; no. 2; pp. 636 - 649
• Main Authors: Hammonds, Jason, Chen, Xuemin, Ding, Lingmei, Fouts, Timothy, De Vico, Anthony, zur Megede, Jan, Barnett, Susan, Spearman, Paul
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 30.09.2003
• Subjects: CD4 antigen; CD4 Antigens - metabolism; Cell Line; Env protein; Envelope; Gag; Gag protein; Gene Products, env - genetics; Gene Products, env - metabolism; Gene Products, gag - chemistry; Gene Products, gag - genetics; Gene Products, gag - metabolism; glycoprotein gp120; gp120; HIV Envelope Protein gp120 - chemistry; HIV Envelope Protein gp120 - metabolism; HIV-1 - genetics; HIV-1 - metabolism; Human immunodeficiency virus 1; Humans; Primary isolate; Pseudovirion; Temperature; Virion - genetics; Virion - metabolism; Virus Assembly; gp120; Gag; Envelope; Pseudovirion; Primary isolate
• ISSN: 0042-6822; 1096-0341
• DOI: 10.1016/S0042-6822(03)00467-7

Human immunodeficiency virus type-1 (HIV-1) particles incorporate a trimeric envelope complex (Env) made of gp120 (SU) and gp41 (TM) heterodimers. It has been previously established that soluble CD4 (sCD4) interaction leads to shedding of gp120 from viral particles, and that gp120 may also be easily lost from virions during incubation or particle purification procedures. In the design of HIV particle or pseudovirion-based HIV vaccines, it may be important to develop strategies to maximize the gp120 content of particles. We analyzed the gp120 retention of HIV-1 laboratory-adapted isolates and primary isolates following incubation with sCD4 and variations in temperature. NL4-3 shed gp120 readily in a temperature- and sCD4-dependent manner. Surprisingly, inactivation of the viral protease led to markedly reduced shedding of gp120. Gp120 shedding was shown to vary markedly between HIV-1 strains, and was not strictly determined by whether the isolate was adapted to growth on immortalized T cell lines or was a primary isolate. Pseudovirions produced by expression of codon-optimized gag and env genes also demonstrated enhanced gp120 retention when an immature core structure was maintained. Pseudovirions of optimal stability were produced through a combination of an immature Gag protein core and a primary isolate Env. These results support the feasibility of utilizing pseudovirion particles as immunogens for the induction of humoral responses directed against native envelope structures.