HIV-1 envelope glycoprotein gp120, negative regulatory factor (Nef), and transactivator of transcription (Tat) viral antigens (gp120/NefTat)

HIV-1 gp120, Nef, and Tat viral antigens constitute a multi-component target used in the development of therapeutic and preventive HIV vaccines [1]. This combination addresses three distinct and essential aspects of the HIV-1 life cycle: gp120 is the primary envelope glycoprotein responsible for viral attachment to host CD4 receptors and co-receptors (CCR5 or CXCR4); Tat (Transactivator of Transcription) is a regulatory protein required for the efficient transcription and elongation of the viral genome; and Nef (Negative Regulatory Factor) is an accessory protein that facilitates immune evasion by downregulating cell-surface molecules such as CD4 and MHC-I [3, 5]. By combining these antigens, researchers aim to elicit a synergistic immune response that includes both neutralizing antibodies to block viral entry and cytotoxic T-lymphocyte (CTL) activity to clear infected cells [6]. This multi-antigen approach, exemplified by clinical candidates like GSK's SB732461, is designed to overcome the limitations of single-antigen vaccines and provide broader protection against diverse HIV-1 clades [1, 2]. Despite promising immunogenicity in early-phase trials, challenges remain regarding the high mutation rate of the virus and the need for durable, protective immune memory [2]. Additionally, these proteins are implicated in HIV-associated neurocognitive disorders (HAND), where gp120 and Tat exert direct neurotoxic effects on the central nervous system by disrupting neuronal signaling and promoting inflammation [4].

Other names

gp120/NefTat fusion proteinHIV-1 envelope and regulatory antigensGSK SB732461 antigensgp120-NefTat

Induction of HIV-specific humoral and cellular immune responses, including neutralizing antibodies against gp120 and CD4+/CD8+ T-cell responses against Nef and Tat, to inhibit viral entry and eliminate infected cells [1, 6].