Anti-Human CD11c [3.9] – Purified in vivo GOLD™ Functional Grade

Clone 3.9 is a monoclonal antibody specific to human CD11c that is commonly used in vivo in mouse studies, primarily with humanized mouse models to detect, characterize, and modulate human myeloid and dendritic cells in a living organism.

Key in vivo applications in mice include:

• Identification and tracking of human CD11c-positive cells: Clone 3.9 enables researchers to identify and monitor human dendritic cells and other myeloid cell populations engrafted in humanized mice, particularly in studies of immune system function, cell migration, and cell depletion.
• Functional modulation or depletion of human CD11c-positive cells: Due to its affinity for the activated form of human CD11c, clone 3.9 can partially block CD11c-ligand interactions and is sometimes used to functionally manipulate or transiently deplete these cells to study their roles during immune responses, infection, or therapy.
• Assessment of immune responses and vaccine efficacy: By targeting human dendritic cells (which express high levels of CD11c), clone 3.9 is used to study antigen presentation, immune activation, or tolerance mechanisms in vivo, including the testing of human-specific immune therapies and vaccines.
• Validation of myeloid lineage chimerism: In mouse models reconstituted with human hematopoietic cells, clone 3.9 enables precise gating and quantification of human myeloid engraftment via flow cytometry, immunohistochemistry, or related methods.

Important context:

• Clone 3.9 recognizes a site in the I domain of CD11c and binds preferentially to the activated form of the integrin, making it useful for detecting functionally relevant subpopulations.
• This antibody is not cross-reactive with mouse CD11c, thus its use is restricted to models where human CD11c is present (e.g., humanized or xenografted mice).
• Recommended in vivo applications require functionally pure, low-endotoxin formulations to avoid nonspecific immune activation in mice.

Summary table of common in vivo applications:

Applications outside of these contexts (e.g., standard mouse strains without human cells) are generally not supported, because clone 3.9 does not bind murine CD11c.

In the literature, CD11c antibodies, such as the CD11c (3.9) Mouse mAb, are commonly used for identifying and studying dendritic cells, which are crucial in the immune system. However, the number "3.9" in this context refers to the specific antibody clone, not a direct association with the number 3.9 as a protein or a particular protein complex.

Other commonly used antibodies or proteins in literature include those targeting specific antigens in autoimmune diseases, cancer, and other conditions:

• Anti-PM/Scl antibodies are associated with scleroderma and myositis.
• Anti-Scl-70 antibodies are used in diagnosing systemic sclerosis.
• Anti-synthetase antibodies (e.g., Jo-1, Mi2) are associated with myositis.
• Therapeutic antibodies like Trastuzumab and Pertuzumab are used in cancer therapy.

While there's no direct mention of a protein or antibody specifically named "3.9" in the broader context of proteins or peptides, the clone designation "3.9" for the CD11c antibody is well-documented in research.

Clone 3.9 is a monoclonal antibody specific for human CD11c, and scientific literature consistently highlights several core findings from its use in immunological research:

• Activation-Specific Binding: Clone 3.9 recognizes only the activated form of CD11c, distinguishing it from other anti-CD11c antibodies that bind both resting and activated forms. This specificity is valuable for identifying and studying activated dendritic cells and monocytes.

• Epitope Specificity: It targets the I domain of the CD11c α-chain, providing precise molecular recognition useful for functional and mechanistic studies.

• Functional Blocking: Clone 3.9 can partially block the interaction between CD11c and its ligand (such as ICAMs), making it a tool for probing the functional roles of CD11c in cell adhesion and migration.

• Common Research Applications: This clone is widely used for:

  • Flow cytometry to analyze immune cell populations, specifically activated dendritic cells in blood and tissues.
  • Immunohistochemistry for localization and identification of CD11c+ cells in histological sections.
  • Functional assays that assess the biological consequences of CD11c activation or blockade.

• Internalization and Targeted Delivery: Studies report that clone 3.9 can trigger internalization of CD11c, which is under investigation for potential receptor-targeted vaccine strategies.

• Citation Usage: Major publications using clone 3.9 include human immunology, hematology, and cell biology studies, particularly in work requiring discrimination between resting and activated immune cells.

Summary Table — Key Features of Clone 3.9 from Citation Analysis

Clone 3.9’s unique properties—especially its selectivity for the activated conformation of CD11c—make it one of the most cited clones in studies targeting activated antigen-presenting cells in both basic and translational immunology.

Dosing regimens for the clone 3.9 antibody (anti-human CD11c) vary significantly across different mouse models and experimental contexts, particularly depending on the intended use (such as immunotherapy, cell depletion, or flow cytometry) and the immune system background of the mice.

Key factors influencing clone 3.9 dosing regimens:

• Mouse model background and immune status: Immunocompromised, humanized, or wild-type mice may require different dosing for efficacy or depletion, due to differences in antibody clearance and immune cell populations.

• Purpose of use:

  • For cell depletion (e.g., human dendritic cells in humanized mice), higher or repeated doses are often used.
  • For in vivo targeting or functional studies (such as blocking assays), doses may be lower and administered as single or multiple injections.
  • Flow cytometry or ex vivo detection use much lower, non-depleting doses.

• Dosing frequency and amount: There is no single standardized regimen; reported doses in the literature and manufacturer protocols typically range from 5–100 μg per injection, often given intravenously (i.v.) or intraperitoneally (i.p.), and administered weekly, biweekly, or as a single administration depending on the study design. Protocols may adjust antibody concentration, injection volume, and frequency based on pilot results or previous studies.

• Antibody isotype and formulation: Different formulations (e.g., "Purified In Vivo GOLD™" or "PLATINUM") may be optimized for in vivo applications and influence dosing selection.

Example Dosing Regimens (from product datasheets and literature)

These values are illustrative; actual regimens should be tailored based on pilot experiments, target cell frequency, and mouse model specifics.

Additional Notes

• Clone 3.9 specificity: It is specific to the human CD11c I domain and preferentially binds the activated form of CD11c.
• Pilot studies are recommended to optimize both specificity and efficacy for the chosen mouse model and endpoint.
• Published studies may provide starting points, but always consult up-to-date datasheets and adjust for your specific model and purpose.

In summary, no universal dosing regimen exists for clone 3.9; the optimal regimen depends on the experimental context, mouse strain, and objective. Doses typically range from 10–100 μg per injection for in vivo studies, with adjustments made based on empirical results and immune system background.