C3d Specific Neutra™ Antibody Products

Are your therapeutic strategies hindered by complex complement-mediated pathologies or inefficient validation of immunomodulatory targets? Creative Biolabs' C3d specific Neutra™ antibody products empower your research with rigorously validated, high-affinity antibodies engineered through advanced recombinant protein platforms. Our solutions enable precise modulation of complement signaling, accelerating drug discovery for inflammatory and autoimmune disorders.

Introduction to C3d

Complement protein C3d, a 35 kDa proteolytic fragment derived from the alpha chain of C3, serves as a critical link between innate and adaptive immunity. It acts as a molecular bridge, enhancing antigen presentation by binding to complement receptor 2 (CR2) on B cells. This interaction amplifies B cell activation and antibody production, positioning C3d as a central regulator in immune complex clearance and pathogen opsonization.

• Structural Insights

C3d adopts a compact, thioester-containing domain structure stabilized by disulfide bonds. Its surface features a conserved binding interface for CR2, facilitating interaction with B cells. Cryo-EM studies reveal that conformational changes in the thioester domain enable covalent attachment to pathogen surfaces, marking them for immune destruction.

• Related Signaling Pathways

C3d intersects with multiple pathways:

1. Complement Cascade: Integrates signals from classical, alternative, and lectin pathways, driving inflammation and pathogen clearance.

2. B Cell Activation: Binding to CR2-CD21 co-receptor complexes lowers the threshold for B cell receptor (BCR) signaling, enhancing antigen-specific antibody responses.

3. Immune Tolerance: Dysregulation of C3d-CR2 interactions contribute to autoantibody production in systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).

Fig.1 CR2 activation by interaction with C3d-opsonized antigen.¹

• Pathological Relevance

Elevated C3d levels correlate with severe inflammatory conditions, including C3 glomerulopathy, age-related macular degeneration, and autoimmune diseases. In cancer, C3d deposition within tumors suppresses anti-tumor immunity by promoting regulatory B cell activity. Therapeutic targeting of C3d offers promise for mitigating complement-driven tissue injury and immune hyperactivation.

Applications of C3d-Neutralizing Antibodies

• Modulating Autoimmune Diseases

Anti-C3d antibodies disrupt CR2-mediated B cell activation, reducing autoantibody production in SLE and RA models. Early-phase trials demonstrate reduced glomerular inflammation in C3 glomerulopathy patients treated with C3d inhibitors.

• Enhancing Cancer Immunotherapy

By neutralizing tumor-associated C3d, these antibodies reverse complement-mediated suppression of cytotoxic T cells. This approach synergizes with checkpoint inhibitors to improve tumor clearance in solid malignancies.

• Managing Chronic Inflammatory Disorders

In age-related macular degeneration, anti-C3d therapies reduce subretinal complement deposition, slowing disease progression. Similarly, neuroinflammatory models show attenuated neuronal damage by blocking C3d-driven microglial activation.

• Advancing Diagnostic Assays

C3d-specific antibodies serve as biomarkers for monitoring disease activity in SLE and predicting renal flare risks. Their high sensitivity supports early intervention in complement-driven pathologies.

Our Anti-C3d Antibodies

Creative Biolabs' anti-C3d antibodies exhibit exceptional specificity for epitopes within the CR2-binding domain, effectively blocking pathogenic immune complex formation. Validated in ELISA, flow cytometry, and immunohistochemistry, these antibodies enable:

- Quantitative assessment of C3d deposition in renal or synovial biopsies.

- Functional studies on complement-mediated B cell hyperactivity.

- Preclinical evaluation of C3d-targeted inhibitors.

Creative Biolabs delivers rigorously validated C3d-specific antibodies tailored to your various research needs.

Contact our scientific team today to discuss customized solutions for your complement-focused projects.

REFERENCE

1. Merle, Nicolas S., et al. "Complement system part II: role in immunity." Frontiers in immunology 6 (2015): 257. Distributed under Open Access license CC BY 4.0, without modification. https://doi.org/10.3389/fimmu.2015.00257