Protein Overview
CD4 is a co-receptor on T helper cells that binds MHC class II on antigen-presenting cells, stabilizing TCR-peptide-MHC engagement and recruiting LCK to the TCR complex, lowering the antigen density required for activation. CD4 also serves as the primary entry receptor for HIV.
Expected Localization
Plasma membrane, single-pass type I transmembrane glycoprotein with four extracellular Ig-like domains.
Expected pattern is membranous/surface labeling of individual lymphocytes and monocytes/macrophages, with occasional low-intensity cytoplasmic signal in monocytic populations.
Expected Expression Pattern
Expressed on T helper (CD4+) lymphocytes, CD4+CD8+ double-positive thymocytes, and at lower levels on monocytes, macrophages, and dendritic cells; found in blood, lymph node, tonsil, spleen, and thymus. Expression can vary with activation state.
Relevant Pathways
- TCR-MHC class II recognition and antigen presentation
- Immune synapse formation
- LCK recruitment and proximal TCR signaling
- T helper cell differentiation (Th1/Th2/Th17/Treg)
- Thymocyte positive/negative selection
- HIV viral entry (gp120 binding)
Clone Information
Antibody Species: Rabbit
Cell Type Compatibility: Validated in human cells only using Cytos™ kits.
For more details on the clone and reactivity with other species, visit ABclonal and search for the clone catalog # A26036PMBCS.
Qualitative Results
Localization Assessment
CD4 protein panel demonstrates strong localization to the cell membrane of a subpopulation of PBMCs. The observed strong expression of CD4 in a subpopulation of PBMC cells is consistent with published data.
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| PBMC |
PBMCs were cultured independently in flasks, spun down to a 12-well format following the user guide for suspension cells, fixed with 4% formaldehyde for 30 minutes, and permeabilized using 70% ethanol for 10 minutes. Cells were then incubated with probe made with biotinylated Rabbit monoclonal anti-CD4 antibody for 1 hour at room temperature. The slide kit was then assembled into a flow cell and loaded onto an AVITI24™ along with the Cytos Protein Cartridge for a multiomics cell screening run. CD4 demonstrated enhanced expression in a fraction of PBMCs, and no obvious expression in Jurkat and Raji cells. These results support high confidence in target-specific detection and validate this antibody as a passing clone.
Quantitative Results
| Signal-to-noise ratio Acceptance criteria: > 2x background |
Pass |
- 6.71 ± 4.15 (PBMC; n=3 runs)
Indicates the fold brightness of the target signal as measured by the Mean Intensity Above (Otsu-defined) Threshold (IAT), over the background (a channel-matched isotype control) in the same cell. The result of 11.47 in PBMCs is over 5 times the acceptance threshold — a clean, easily distinguishable signal in the CD4-positive subpopulation.
|
Panel-level run-to-run reproducibility |
Pass |
For each imaging panel, we assess reproducibility by comparing the intensity signal a given antibody target produces across independent replicate runs. Within each run, we measure the average per-well fluorescence intensity for every target in the panel. We then plot each target's intensity from one run against the matching target's intensity from another run of the same layout, and calculate the Pearson correlation coefficient (r) between those two sets of measurements. Squaring that value gives the R² (coefficient of determination), which reports what fraction of the variation in one run's signal is explained by the other run's signal.
Disclaimer: This information is provided to help assess whether the target suits your experiment. It reflects internal testing conditions and does not guarantee performance in your application. Performance in other cell types and species such as mouse or rat may require additional validation using Cytos kits as performance is not guaranteed.
ELEMENT BIOSCIENCES For Research Use Only. Not for Use in diagnostic procedures.