Anti-CD4 Rabbit Polyclonal Antibody for WB, IF/ICC, IF-P, ELISA - P01730

Core Product Specifications and Parameters

Biological Background: CD4 Function and Localization

• CD4 is a 51 kDa integral membrane glycoprotein also known as T-cell surface antigen T4/Leu-3, belonging to the immunoglobulin superfamily. It contains four extracellular Ig-like domains (D1–D4), a single transmembrane helix, and a cytoplasmic tail that interacts with the Src kinase LCK.
• In T-helper cells, CD4 functions as a coreceptor for MHC class II molecules. It simultaneously binds the T-cell receptor (TCR) and MHC class II on antigen-presenting cells, recruiting LCK to phosphorylate TCR-CD3 complex substrates, which initiates signaling cascades leading to T-cell activation, lymphokine production, and proliferation.
• CD4 is critical for thymocyte development and the differentiation of T-helper cells. It also triggers monocyte-to-macrophage maturation, underscoring its role in innate and adaptive immunity.
• Beyond T cells, CD4 is expressed in macrophages, dendritic cells, and NK cells, where it modulates differentiation, cytokine expression, and cell migration through TCR/LCK-independent pathways.
• CD4 serves as the primary receptor for human immunodeficiency virus-1 (HIV-1) via its D1 domain, facilitating viral entry. It is also a receptor for Human Herpes virus 7 (HHV-7). HIV-1 infection leads to CD4 downregulation by the viral protein Vpu. Related references: PMID:12089508, PMID:16331979, PMID:2214026, PMID:17346169, PMID:7909607
• Subcellular localization is predominantly at the cell membrane, consistent with its function as a surface receptor. A soluble form can be shed upon T-cell activation.
• It is highly expressed in T-helper cells but also found in other immune cells such as macrophages, dendritic cells, and NK cells. CD4 expression is a defining marker for T-helper cell identification.
• Post‑translational modifications include N‑linked glycosylation, disulfide bonds within Ig domains, and palmitoylation at the cytoplasmic tail, which may modulate membrane microdomain localization and signaling.

Experimental Guidance and Technical Tips

• The immunogen spans the extracellular domain (aa 26‑200) of human CD4, covering the MHC class II and HIV-1 gp120 binding sites. This design may enable detection of full‑length CD4 in denaturing western blots as well as native conformations in immunofluorescence and ELISA.
• For western blotting, a band around 51 kDa is expected under reducing conditions. Glycosylation can cause the apparent molecular weight to appear higher (55–60 kDa). Include appropriate positive controls (e.g., Jurkat or human PBMC lysates) and consider using a reducing agent.
• Reported cross‑reactivity with mouse and rat CD4 should be verified in your specific experimental models. Sequence alignment shows ~70% identity in the extracellular region; titration of the primary antibody and careful validation are recommended.
• The antibody can be applied in indirect immunofluorescence (IF/ICC) and ELISA formats. Ensure appropriate fixation and permeabilization protocols for IF; for cell‑surface staining, avoid permeabilization. Validate in the relevant cell type or tissue.
• When using for functional studies (e.g., blocking of HIV‑1 binding), note that the polyclonal nature may yield variable results; monoclonal formats may be preferred for consistent epitope‑specific blockade.

CamelBio: Your One-Stop Sourcing Bridge

CamelBio equips diagnostic manufacturers, research laboratories, and institutes with a comprehensive one‑stop supply chain for IVD raw materials. For CD4‑related immunoassay development—whether for T‑cell phenotyping, HIV research, or immune monitoring—we provide validated antibody pairs, optimized monoclonal/polyclonal antibodies, and bulk ancillary reagents. Our sourcing expertise can accelerate your project from concept to clinic, including rare‑target raw‑material acquisition and technical consultation.