Anti-Human CD19 [Clone 4G7] – Purified in vivo GOLD^TM Functional Grade

In Vivo Applications of Clone 4G7 in Mice

Clone 4G7 is a monoclonal antibody specific to human CD19, a marker predominantly expressed on normal and malignant B lymphocytes. While originally developed for human applications, its engineered derivatives and use in xenograft or transgenic mouse models have enabled a range of in vivo studies.

Functional Depletion and Targeting of B Cells

A primary in vivo use of clone 4G7—or its murine CD19-targeting derivatives—is to deplete or functionally modulate B cells in mouse models. This is especially relevant in studies of B cell biology, autoimmune diseases, and B cell malignancies. By targeting CD19, 4G7 can deplete B lymphocytes, block their function, or deliver payloads to these cells. However, most direct literature describes human CD19 targeting, so for mouse B cell depletion, murine-specific anti-CD19 clones (not 4G7) are typically used.

Development and Testing of CAR-T Therapies

CD19-targeting single-chain variable fragments (scFv) derived from 4G7 are widely used in the engineering of chimeric antigen receptor T cells (CAR-T) for preclinical and clinical development. Mice are commonly used as hosts for human tumor xenografts to evaluate the efficacy and safety of 4G7-based CAR-T therapies targeting CD19-expressing malignancies. In these models, human tumor cells (e.g., B cell lymphomas or leukemias) are engrafted into immunodeficient mice, which are then treated with CAR-T cells expressing the 4G7-derived anti-CD19 scFv.

Detection and Characterization

4G7 can be used for epitope mapping, immunophenotyping, and tracking of human CD19+ cells in vivo, especially in xenograft or humanized mouse models. Flow cytometry with fluorescently labeled 4G7 allows for the detection and quantification of human B cells in these systems.

DNA-Encoded Monoclonal Antibody (DMAb) Studies

Recent biotechnological advances have enabled in vivo expression of monoclonal antibodies via DNA plasmids. For example, the gene encoding 4G7 (as a chimeric mouse/human IgG1) has been delivered to mice via intramuscular injection followed by electroporation, allowing for the in vivo production and systemic delivery of the antibody. This approach bypasses the need for repeated protein injections and can be used to study antibody pharmacokinetics, efficacy, and safety.

General In Vivo Dosing Considerations

While direct in vivo dosing regimens for 4G7 in mice are not widely standardized, general practices for monoclonal antibodies suggest doses of 100–250 µg per mouse, administered intraperitoneally every 2–3 days for sustained exposure. However, specific regimens depend on the application (e.g., antibody-mediated depletion, checkpoint blockade, or tumor targeting), the mouse model (immunocompetent vs. immunodeficient), and the desired pharmacokinetic profile. When using DNA-encoded approaches, a one-time plasmid injection can drive sustained antibody expression in vivo.

Table: Common In Vivo Applications of Clone 4G7 in Mice

Summary

• Clone 4G7 is primarily used in vivo in mice for studying human CD19+ B cell biology, developing and testing 4G7-based CAR-T cell therapies (using human xenografts), and detecting/tracking human B cells in immune-deficient or humanized mouse models.
• For direct B cell depletion in mice, murine-specific anti-CD19 antibodies (not 4G7) are typically used.
• 4G7 has also been expressed in vivo via DNA-encoded platforms, allowing novel preclinical studies of systemic antibody delivery and persistence.
• Dosing regimens are context-dependent and should be tailored to the specific experimental goals.

For precise protocols, researchers should consult peer-reviewed studies using 4G7 in their exact disease or model context, as published regimens are highly application-specific.

Commonly used antibodies or proteins in the literature with 4G7 (anti-human CD19) include additional B cell and lineage markers, anti-idiotype antibodies, and relevant isotype or functional controls, especially in flow cytometry and CAR-T detection setups.

Key antibodies and proteins commonly used alongside 4G7:

• Other B-cell markers: These include CD20, CD22, and CD45, which are frequently co-stained with CD19 (4G7) to delineate B-cell populations more fully in immunophenotyping panels. Using multiple B-cell markers is standard in flow cytometry for robust gating strategies.

• Anti-idiotype antibodies (e.g., clones A8 and E1): These are raised against the idiotype of the 4G7-derived CARs and used in blocking assays and flow cytometry to specifically identify 4G7-based CAR-T cells.

• Isotype controls: Appropriate isotype controls are used for specificity and background correction in flow cytometry experiments involving 4G7.

• T cell or other lineage markers: When characterizing immune populations or monitoring CAR-T efficacy, researchers often co-stain with CD3 (T cell marker), CD4/CD8 (T-cell subsets), or CD56 (NK cells).

• Negative and positive controls: Antibodies targeting non-B-cell markers (e.g., EpCAM, CD47, EGFR) are sometimes used in parallel experiments as controls or to broaden phenotyping panels.

• Functional or signaling markers: In some studies, additional proteins such as intracellular cytokines or markers of activation (e.g., CD69, CD25) are utilized alongside 4G7 to assess functional properties of identified B cells.

Example combinations reported in the literature:

• Flow panels: CD19 (4G7), CD20, CD22, CD45, CD3, CD4, CD8.
• CAR detection: 4G7 (for CAR presence), anti-idiotype antibodies (A8, E1) for specificity, plus anti-CD3 or CD45 for lymphocyte gating.

This combinatorial approach allows for precise B-cell quantification, CAR-T visualization, and robust immunophenotyping in both research and clinical contexts.

Key findings from clone 4G7 citations in scientific literature indicate that this monoclonal antibody is a crucial reagent for detecting and studying human CD19, specifically marking both normal and malignant B lymphocytes, making it valuable for research, diagnostic, and clinical applications.

Essential context and supporting details:

• Development and specificity: Clone 4G7 was generated by immunizing mice with chronic lymphocytic leukemia (CLL) cells. It is specific for human CD19, an antigen expressed on the surface of B cells across development, and recognizes both healthy and cancerous B lymphocytes.
• Diagnostic use: Its ability to distinguish B cells has established 4G7 as a key reagent for immunophenotyping (classifying cells by their surface markers), aiding diagnosis of B cell malignancies and other hematologic disorders.
• Role in CAR T cell and CAR detection studies: The single-chain variable fragment (scFv) derived from 4G7 is employed in the construction of chimeric antigen receptors (CARs) used in cell therapies targeting CD19, such as UCART19 and ALLO-501. New antibodies against these CARs (that include a 4G7-derived scFv) enable specific, high-affinity detection, monitoring expression, and pharmacokinetics of these therapeutic receptors in preclinical and clinical studies.
• Binding properties: Antibodies and reagents derived from 4G7 show high to very high affinity for their target (dissociation constant, Kd, ranging from 0.1–5 nM), which is key for sensitive and specific detection in flow cytometry and related applications.
• Epitope specificity and blocking: Some literature also references that clone 4G7 recognizes a unique epitope on CD19, and its staining can be partially blocked by certain other antibodies (e.g., clone HIB19), providing insights into CD19 antigenic structure and antibody compatibility.
• Broad impact in research and industry: 4G7 is frequently cited in antibody panel descriptions, clinical protocols (especially for flow cytometry), manufacturing quality control, and as a reference antibody in CD19 occupancy studies.

Additional relevant information:

• Clone 4G7 is distinguished from other anti-CD19 antibodies (e.g., FMC63, SJ25C1) by its epitope specificity and compatibility in multiplexed assays, which impacts choice in clinical and research settings.
• 4G7-derived constructs are central to several cell therapy products currently in clinical development, showing wide utility beyond basic research.

In summary, clone 4G7 is a foundational tool in immunology and hematology for identifying B cells, supporting both innovation in CAR T therapy and ongoing advances in clinical diagnostics.

There are no direct data in the provided search results on the dosing regimens of clone 4G7 (anti-CD19) in mouse models. The existing materials on clone 4G7 focus mainly on its antigen recognition (human CD19) and its use in research tools, such as flow cytometry and detection assays, rather than on in vivo administration in mice. Additionally, while there is extensive discussion about dosing strategies for other murine-targeting antibodies in mouse models—detailing specific doses, routes, and schedules for immune checkpoint (e.g., PD-1, CTLA-4), T cell-depleting, and neutrophil-depleting antibodies—clone 4G7 is not mentioned in these dosing guidelines.

Indirect context: Clone 4G7 is referenced in the context of generating reagents to detect anti-CD19 CAR T cells derived from 4G7, but the dosing of 4G7 itself as a therapeutic or experimental agent in mice is not described. Notably, anti-CD19 CAR T cell therapy in mouse models has been explored with dose-dependent effects on efficacy and toxicity, but these studies do not discuss dosing of 4G7 as a monoclonal antibody.

Gaps and limitations: The search results do not clarify whether clone 4G7 is ever used for direct injection into mice (e.g., for B cell depletion or therapy), or if its use is limited to ex vivo or in vitro assays. There is also no information about how dosing might differ across various mouse models (e.g., tumor, autoimmune, or infection models).

Summary Table: Dose Regimen Data Availability

Key Points

• No published dosing regimens for clone 4G7 in mouse models are cited in the provided results.
• Other antibody clones targeting immune molecules have well-documented dosing guides for mice, but 4G7 is not among them.
• Clone 4G7 is primarily referenced as a tool for detecting CD19 and CAR T cells, not as a therapeutic agent administered to mice.

If you require dosing data for clone 4G7 in mice, it is not available in the current search results and you may need to consult specialized literature, contact the antibody vendor, or refer to original research publications that specifically detail in vivo use of this clone in mouse models.