Anti-Mouse CD24 (Clone M1/69) – Purified in vivo GOLD^TM Functional Grade

Clone M1/69, a rat monoclonal antibody specific to mouse CD24, is widely used in various in vivo applications involving mouse research. Some of the common applications include:

1. Flow Cytometry and Cell Sorting: M1/69 is frequently used for the precise identification, quantification, and sorting of CD24-expressing cells, such as B cells, dendritic cells, granulocytes, and erythrocytes, particularly in bone marrow and spleen.

2. Immunophenotyping: It aids in the characterization and profiling of murine cell types, including myeloid cells and thymocytes, through immunophenotyping techniques.

3. In Vivo Studies: Clone M1/69 is used in in vivo mouse studies to study immune cell differentiation, function, and glycosylation biology centered on CD24/HSA. It helps in cell population identification and isolation.

4. Studying B-Cell Development: Expression of CD24 is crucial for resolving stages of B-cell development in mouse bone marrow, making M1/69 a valuable tool for studying B-cell lymphopoiesis and related pathologies.

5. Investigating Autoimmunity and Cancer: CD24 plays a role in regulating B-cell proliferation and maturation, and its interaction with P-selectin suggests involvement in cell adhesion and signaling, making it relevant for studying autoimmune regulation and cancer biology.

Commonly used antibodies or proteins alongside M1/69 (anti-CD24) in the literature include markers for distinguishing hematopoietic cell subsets, most notably those recognizing B-cell development, T cells, myeloid cells, and stem/progenitor populations.

Key antibodies or proteins frequently used with M1/69:

• CD45 (clone M1/9.3): A pan-leukocyte marker commonly used for identifying and gating all hematopoietic (non-erythroid) cells.
• B-cell markers:
  • B220 (CD45R)
  • CD19
  • IgM/IgD for B-cell maturityThese are often combined with CD24 (M1/69) to resolve stages of B-cell development.
• T-cell markers:
  • CD3
  • CD4
  • CD8These can be used to distinguish T lymphocytes from B cells and other lineages.
• Stem/progenitor markers:
  • c-Kit (CD117)
  • Sca-1
  • CD34These help define early progenitor or stem cell populations alongside CD24.
• Other hematopoietic/immune markers:
  • CD11b (myeloid lineage)
  • Gr-1 (granulocytes)
  • TER-119 (erythroid lineage, to exclude red cell progenitors)
• P-selectin (CD62P): CD24 has been shown to interact with P-selectin, so this can also be included in studies of cell adhesion and signaling.

CD24 (M1/69) is variably glycosylated on different cell populations, so it is typically used in panel analysis with these other antibodies to distinguish between cell types and maturation stages. The use of M1/69 with M1/9.3 (CD45) is especially well documented for removal and discrimination of shared antigens during monoclonal antibody development and cell sorting.

In summary, M1/69 is most commonly used with markers for:

• CD45 (M1/9.3)
• Major B-cell and T-cell markers (B220, CD19, IgM, CD3, CD4, CD8)
• Stem/progenitor and myeloid lineage markers (c-Kit, Sca-1, CD11b, Gr-1)
• CD62P (P-selectin) in functional binding or adhesion studies

Clone M1/69 is a well-characterized rat monoclonal antibody that targets mouse CD24, also known as the heat-stable antigen (HSA), and is widely cited in immunological and cell biology research for its utility in characterizing and isolating murine cell types.

Key findings from M1/69 citations in scientific literature include:

• Molecular Target and Structure:
  M1/69 recognizes CD24, a glycosyl-phosphatidylinositol (GPI)-anchored surface molecule found on various murine cells, including thymocytes, B and T lymphocytes, erythrocytes, myeloid, and dendritic cells. The underlying peptide is extremely small (30 amino acids post-signal sequence), but the functional mass of CD24 is mainly due to extensive N- and O-linked glycosylation, making it highly heterogeneous between cell types.

• Role in Cell Biology and Immunology:
  CD24 detected by M1/69 is heavily used in flow cytometry and immunophenotyping to distinguish and isolate immune cell stages, particularly for:

  • Profiling B cell maturation and lymphopoiesis in the mouse bone marrow.
  • Identifying dendritic cells, myeloid populations, and thymocyte subsets.
  • Mapping immune cell differentiation and function, including events such as thymocyte maturation, immunoglobulin class switching in B cells, and terminal differentiation of macrophages.
  • Isolating populations for downstream molecular analyses (sorting, gene/protein expression studies).

• Biochemical and Functional Specificity:

  • CD24 (M1/69/J11d antigen) expression is downregulated or extinguished at specific stages of immune cell maturation, making it a useful marker for delineating cell development and differentiation.
  • The functional diversity of CD24 is attributed to differential glycosylation, not the peptide backbone, allowing for cell-type–specific biological roles.
  • There is evidence that CD24 can interact with P-selectin (CD62P), hinting at potential roles in cell adhesion and trafficking.
  • Different anti-CD24 clones (such as M1/69, J11d, and 30-F1) may show subtle differences in staining, emphasizing the need for consistency in research applications.

• Experimental Applications:

  • M1/69 is a standard tool for flow cytometric analysis, immunohistochemistry, immunofluorescence, and cell sorting in mouse models.
  • Its specificity and broad expression make it instrumental for investigating murine immune system development, function, and disease.

Summary Table: Key Features of M1/69 and Its Use

In essence, citations of clone M1/69 establish it as an essential immunological reagent for dissecting the composition and maturation of the mouse immune system, with particular attention to CD24’s role in cell differentiation and immune cell subset analysis.

Dosing regimens of clone M1/69 (anti-mouse CD24) are not standardized and vary significantly between studies and mouse models. Unlike many commonly used monoclonal antibodies in mice—such as anti-PD-1, anti-PD-L1, or anti-CTLA-4, for which detailed dose ranges, schedules, and routes (e.g., 200–500 μg per mouse intraperitoneally every 3–4 days) are well established in the literature—there are no commonly cited protocols for in vivo dosing of M1/69 in the available search results.

Key Observations on Dosing Variability

• Published Protocols and Vendor Details: No commonly referenced dose ranges or schedules for M1/69 in vivo administration are listed in vendor datasheets or major protocol repositories. Vendors and academic sources emphasize that M1/69 is widely used for immunophenotyping and flow cytometry, but provide minimal guidance on in vivo use.
• Research Context: M1/69 is primarily used as a tool for characterizing and isolating murine immune cells (e.g., dendritic cells, myeloid cells, thymocytes) in vitro. Its role in vivo is less characterized, and dosing is typically determined on a case-by-case basis depending on the experimental question, mouse strain, and desired biological effect.
• Lack of Standardization: The absence of standardized dosing contrasts with other antibodies (e.g., checkpoint inhibitors, cell-depleting antibodies), where target engagement, pharmacokinetics, and biological effects are better understood, and dosing is optimized for those purposes.
• Recommended Practice: For in vivo studies, researchers are advised to consult the primary literature for similar models and to perform pilot experiments to determine the optimal dose and schedule for their specific experimental system. This is especially important given that even in vitro, subtle differences in staining are observed between lymphocyte subpopulations, suggesting that biological activity may be context-dependent.

Summary Table: M1/69 vs. Standard Antibody Dosing

Conclusion

Dosing regimens for M1/69 vary widely and are not well documented for in vivo use in mice. Researchers must rely on published studies in similar models or optimize dosing empirically for their specific experimental needs. This variability stands in contrast to other monoclonal antibodies with established in vivo dosing guidelines. If you plan to use M1/69 in vivo, a thorough literature review and pilot experiments are essential to determine appropriate dosing.