The HIV-1 entry process is one of the most finely orchestrated molecular events in virology. It begins with a single, indispensable interaction: the binding of the viral envelope glycoprotein gp120 to the CD4 receptor on the surface of host T cells. This initial engagement triggers a cascade of conformational changes that ultimately allow the virus to fuse with the host cell membrane and establish infection. For over four decades, CD4 has stood at the centre of HIV research—not merely as a receptor to be blocked, but as a molecular handle for understanding viral entry, developing neutralising antibodies, designing entry inhibitors, and even engineering cell-targeted gene therapies.
Among the many tools that enable this research, HIV Biotinylated hCD4 , HIV CD4 , and HIV hCD4 recombinant proteins have emerged as essential reagents for researchers working at the intersection of virology, immunology, and therapeutic development. Each format serves a distinct purpose—from high-throughput binding assays to immunogen design—and together they illustrate the full spectrum of CD4-based research applications.
HIV CD4: The Foundation of Receptor-Binding Studies
The HIV CD4 recombinant protein represents the extracellular domain of the human CD4 receptor, the primary entry receptor for HIV-1. This protein is indispensable for studying the molecular details of the gp120-CD4 interaction—the first and most critical step in the HIV entry cascade.
Recent research has revealed the remarkable sophistication of this interaction. A 2026 study demonstrated that the endosomal proteins EHD1 and EHD4 regulate the cell surface expression of CD4, thereby directly contributing to HIV-1 entry. Understanding these regulatory mechanisms requires precisely characterised recombinant CD4 proteins that faithfully recapitulate the native receptor's binding properties. The HIV CD4 protein, available in multiple domain configurations (aa 26-206 and aa 1-398), provides researchers with the flexibility to study different aspects of receptor function—from the N-terminal domain that directly contacts gp120 to the full extracellular region that encompasses all four immunoglobulin-like domains.
HIV hCD4: Full-Length Receptor for Comprehensive Functional Studies
While truncated CD4 proteins are suitable for many binding assays, the HIV hCD4 recombinant protein offers the full extracellular domain (aa 1-398), providing a more complete representation of the native receptor. This format is particularly valuable for studies that require the full structural context of the CD4-gp120 interaction.
The importance of full-length CD4 reagents has been underscored by recent advances in HIV cure research. CD4-directed nanoblades—virus-like particles engineered with anti-CD4 nanobodies—have demonstrated the ability to selectively deliver CRISPR-Cas9 gene-editing machinery into CD4+ cells, achieving efficient HIV proviral DNA disruption and reducing viremia in humanised mouse models. The development of such targeted delivery systems relies on thoroughly characterised CD4 reagents for validating targeting specificity and evaluating off-target effects.
HIV hCD4 is also central to the development of next-generation HIV inhibitors. Recent work has described gp120-specific CD4 (gCD4), a stabilised variant that exhibits enhanced thermostability and retains Env binding while avoiding class II MHC engagement. These CD4-based biologics represent a new class of HIV inhibitors with best-in-class specificity and pharmacokinetic properties—and their development depends on access to high-quality recombinant CD4 reference materials.
HIV Biotinylated hCD4: Precision Tools for High-Throughput Assays
The HIV Biotinylated hCD4 protein adds an additional dimension of utility: site-specific biotinylation that enables immobilisation on streptavidin-coated surfaces without compromising protein function. This format is particularly valuable for high-throughput screening, surface plasmon resonance (SPR), and other assay formats that require oriented, uniform protein capture.
Biotinylated CD4 proteins have become indispensable in the development and validation of HIV entry inhibitors. Recent work has described antibody-drug conjugates (ADCs) that combine CD4-mimetic small molecules with neutralising antibodies as novel HIV-1 entry inhibitors. The development of such dual-warhead ADCs requires robust binding assays that can simultaneously evaluate both the small-molecule and antibody components—assays that are ideally suited to biotinylated CD4 capture platforms.
The HIV Biotinylated hCD4 format offers several distinct advantages:
Oriented Immobilisation: Biotin-streptavidin capture ensures consistent protein orientation, critical for reproducible binding measurements.
Multiplexing Compatibility: Biotinylated proteins can be incorporated into bead-based or array-based multiplexed assays.
Flexible Detection: The His tag enables additional detection and purification options, providing versatility across different experimental platforms.
ELISA and SPR Applications: The protein is validated for ELISA applications, making it suitable for both standard plate-based assays and advanced label-free binding studies.
How to Choose and Buy?
At BOT Bioscience , we are committed to providing premium-quality Infectious Disease Targets to support your cutting-edge research in HIV virology, vaccine development, and therapeutic discovery. Our Infectious Disease Targets portfolio features:
High purity and biological activity validated across multiple applications
Broad coverage of viral, bacterial, parasitic, and fungal targets
Multiple formats: recombinant proteins, antibodies, and ELISA kits
Flexible labelling options: biotin, His tag, and custom conjugations
Rigorous quality control for consistent batch-to-batch performance
Custom protein expression and conjugation services upon request
For researchers interested in exploring Infectious Disease Targets for HIV research, entry inhibitor development, or vaccine studies, BOT Bioscience offers comprehensive technical support and customisation services to meet your specific project requirements. Please Contact us or send an email at info@bot-bioscience.com for product inquiries, quotations, and more detailed information.