CD5 Antibodies

Structure of CD5

CD5 is composed of three highly conserved extracellular immunoglobulin-like domains (V-type domains), and its amino acid sequence has approximately 60-70% homology among different mammals. The N-terminal of this protein contains multiple glycosylation sites, and these modifications are crucial for its immune function. The intracellular segment of CD5 contains multiple tyrosine residues, which can participate in signal transduction. Structurally, CD5 belongs to the scavenger receptor cysteine-enriched (SRCR) superfamily, and its extracellular region contains three consecutive SRCR domains, forming a typical β -folding structure. This special conformation enables it to specifically bind to ligands such as CD72. The transmembrane region of CD5 is composed of 23 hydrophobic amino acids, while the intracellular segment contains multiple conserved protein kinase action sites. These structural features jointly determine its key role in immune regulation.

Fig. 1 Simplified schematic illustration of mAuNPs–anti-CD52B conjugate formation and the SPR-based direct and indirect sandwich immunoassay for CD5 detection.¹

Key structural properties of CD5:

• Contains three highly conserved extracellular immunoglobulin-like domains (V-domain)
• Scavenger receptors that are rich in cysteine (SRCR) features of super family structure
• Across the membrane area consists of 23 hydrophobic amino acids
• Intracellular section contains multiple tyrosine phosphorylation site

Functions of CD5

The main function of the CD5 gene is to regulate the activation and signal transduction of immune cells, and it also plays a significant role in various pathophysiological processes.

The interaction between CD5 and its ligand CD72 exhibits specific binding characteristics, and its signal transduction is dose-dependent, indicating its precise regulatory role in immune balance. Unlike typical immune-activating receptors, CD5 mainly functions through inhibitory signaling pathways, a characteristic that makes it an important research target for autoimmune diseases and tumor immunotherapy.

Applications of CD5 and CD5 Antibody in Literature

1. Alotaibi, Faizah, et al. "Reduced CD5 on CD8+ T cells in tumors but not lymphoid organs is associated with increased activation and effector function." Frontiers in Immunology 11 (2021): 584937. https://doi.org/10.3389/fimmu.2020.584937

The article indicates that in the 4T1 breast cancer mouse model, the expression of CD5 in CD4+ T cells is higher than that in CD8+ T cells. The CD5 level of tumor-infiltrating T cells (TILs) is lower than that of peripheral organs, and CD8+ TILs with low CD5 exhibit stronger activation and effector functions. CD5 may be negatively correlated with the anti-tumor activity of T cells and may become a new target for immunotherapy.

2. Alisjahbana, Arlisa, et al. "CD5 surface expression marks intravascular human innate lymphoid cells that have a distinct ontogeny and migrate to the lung." Frontiers in Immunology 12 (2021): 752104. https://doi.org/10.3389/fimmu.2021.752104

Research has found that CD5+ innate lymphoid cells (ILCs) exist in humanized mouse models, mainly located in the pulmonary vascular and circulatory systems. Unlike conventional CD5-ILCs, CD5+ ILCs originate from the thymus/spleen and have a unique developmental pathway, containing mature ILC1s (producing IFNγ) and immature ILCs, or act as "blood sentinels" to participate in pulmonary immune defense.

3. Ma, Dongshen, et al. "Molecular subtyping of CD5+ diffuse large B-cell lymphoma based on DNA-targeted sequencing and Lymph2Cx." Frontiers in Oncology 12 (2022): 941347. https://doi.org/10.3389/fonc.2022.941347

Studies have found that CD5+ diffuse large B-cell lymphoma (DLBCL) has a poor prognosis, often with MCD subtypes (MYD88/CD79B mutations) and ABC origin. High-frequency mutations in PIM1, MYD88, and KMT2D, as well as double expression of MYC/BCL2, suggest a poor prognosis, while those with high expression of MME have a longer survival period.

4. Naso, Julia R., et al. "CD5 Immunoreactivity Is Associated With Longer Overall Survival in Thymic Carcinoma: A Brief Report." JTO Clinical and Research Reports 6.5 (2025): 100803.https://doi.org/10.1016/j.jtocrr.2025.100803

The research found that the prognosis of patients with CD5-positive thymic carcinoma (≥50% tumor cell staining) was significantly improved: the 3-year overall survival rate reached 100% (only 48% in the CD5-negative group). Multivariate analysis confirmed that CD5 is an independent prognostic factor (HR=0.18, p=0.005) and may become a novel prognostic marker.

5. Ma, Xiao‐bo, et al. "Coexpression of CD 5 and CD 43 predicts worse prognosis in diffuse large B‐cell lymphoma." Cancer Medicine 7.9 (2018): 4284-4295. https://doi.org/10.1002/cam4.1674

Research has found that patients with diffuse large B-cell lymphoma (DLBCL) co-expressing CD5/CD43 have the poorest prognosis: 5% of patients have co-expression, and their event-free survival (EFS) and overall survival (OS) are significantly lower than those with single expression (P<0.001), which is an independent adverse prognostic factor.

Creative Biolabs: CD5 Antibodies for Research

Creative Biolabs specializes in the production of high-quality CD5 antibodies for research and industrial applications. Our portfolio includes monoclonal antibodies tailored for ELISA, Flow Cytometry, Western blot, immunohistochemistry, and other diagnostic methodologies.

• Custom CD5 Antibody Development: Tailor-made solutions to meet specific research requirements.
• Bulk Production: Large-scale antibody manufacturing for industry partners.
• Technical Support: Expert consultation for protocol optimization and troubleshooting.
• Aliquoting Services: Conveniently sized aliquots for long-term storage and consistent experimental outcomes.

For more details on our CD5 antibodies, custom preparations, or technical support, contact us at email.