Anti-Mouse CD11b – Purified in vivo PLATINUM™ Functional Grade

Clone M1/70 is widely used in in vivo mouse studies for several applications related to CD11b-expressing cells, such as macrophages, monocytes, neutrophils, and some dendritic cells and NK cells. Common in vivo applications include:

• Depletion of CD11b-expressing cells: The M1/70 antibody can be used to deplete cells expressing CD11b, which helps in studying the role of these cells in various biological processes.
• Neutralization and blocking: This antibody can block the function of CD11b, which is part of the Mac-1 complex involved in cell adhesion and complement receptor activity.
• Detection and tracking of CD11b+ cells: It serves as a marker to detect and track CD11b-expressing cells in vivo, aiding in understanding their role in immune responses.
• In vivo studies to examine immune cell function: The antibody is used in in vivo studies to investigate the function of CD11b+ cells in immune responses, inflammation, and disease models.

The M1/70 antibody targets CD11b (Integrin alpha M, ITGAM), a common marker for monocytes, macrophages, neutrophils, microglia, and other myeloid cells. In the literature, several other antibodies and proteins are routinely used alongside M1/70, depending on the application (e.g., flow cytometry, immunohistochemistry, lineage depletion, or cell subset identification).

Commonly used antibodies or proteins with M1/70 include:

• CD18 (Integrin beta 2): Forms a heterodimer with CD11b to make Mac-1/CR3. Studies often use antibodies against both CD11b and CD18 to assess or deplete myeloid lineages.
• CD45: A pan-leukocyte marker, used in combination to distinguish hematopoietic from non-hematopoietic populations.
• F4/80: A classical macrophage marker in mice, co-staining with CD11b helps distinguish macrophage subsets.
• Ly6G (Gr-1): A marker for neutrophils; often used with CD11b to identify granulocyte and monocyte populations.
• CD14: Another myeloid/monocyte marker. Used to refine identification of monocytes/macrophages along with CD11b.
• CD3, CD19, NK1.1 (lineage exclusion): For negative selection/depletion of T, B, and NK cells, respectively, when isolating pure myeloid or microglial populations.
• CD24, CD16/32, and other tissue-specific or activation markers: For further subtyping within myeloid or dendritic cell lineages.
• I-A/I-E (MHC II): Used in combination to distinguish between activated antigen-presenting myeloid cell subsets.
• Chemokine receptors (e.g., CCR2, CX3CR1): To separate monocyte and macrophage subsets in tissues.

Typical combinations by research context:

Citations in the literature frequently describe panels including several of the above markers, adapted for tissue specificity and purpose.

Key point: The specific choice of accompanying antibodies depends on the target cell population, the tissue source, and the experimental question, but CD11b (M1/70) is rarely used in isolation in modern immunological studies.

Clone M1/70 is a monoclonal antibody primarily targeting CD11b (integrin alpha-M), widely cited in scientific literature for its role in immunological research. The key findings from M1/70 citations are:

• Epitope and Target Specificity: M1/70 specifically binds to mouse CD11b, a component of the Mac-1 integrin complex (CD11b/CD18), which is involved in cell adhesion and migration. It is also cross-reactive to human CD11b, enabling its use in both mouse and human systems.

• Expression Profiling:

  • CD11b is expressed on monocytes/macrophages, granulocytes, dendritic cells, NK cells, and microglia.
  • Expression is upregulated during monocyte maturation and varies among tissue-resident macrophages.
  • CD11b is commonly used as a microglial marker in nervous tissue and is a key identifier for myeloid lineage cells in flow cytometry and immunophenotyping assays.

• Experimental Utility:

  • Flow cytometry: M1/70 is widely used to identify and quantify CD11b+ populations in immune cells from spleen, bone marrow, brain, and blood. It is also applied in immunoprecipitation and immunohistochemistry (only on frozen tissue, not formalin-fixed paraffin-embedded).
  • Functional blocking: The antibody can block CD11b function in vitro, such as inhibiting iC3b binding and Mac-1 mediated adhesive interactions.
  • Inflammatory studies: M1/70 has been used to probe inflammatory responses. It can induce a pro-inflammatory reaction in Mac-1 expressing cells, especially macrophages, and elevates cytokine levels like IL-6, TNF-α, and MCP-1 upon injection.
  • Tumor and immunological research: M1/70-mediated inhibition of Mac-1/CD11b can suppress myeloid cell recruitment into inflamed or irradiated tumors, affecting immune responses and enhancing tumor treatment efficacy.

• Limitations and Recommendations:

  • M1/70 is not recommended for immunohistochemical staining of formalin-fixed paraffin-embedded tissues, but suitable for frozen tissue and cell suspensions.
  • Antibody concentrations and titrations need empirical optimization for specific experimental setups.

• Disease Associations:

  • Dysfunction of CD11b (detected with M1/70) is linked to conditions such as systemic lupus erythematosus and contributes to pathological immune cell recruitment in inflammatory diseases.

• Mechanistic Insights:

  • CD11b interacts with multiple ligands (ICAM-1, iC3b, fibrinogen), mediating key cell-cell and cell-matrix interactions crucial to immune cell trafficking and function.

Summary table of key findings:

These findings establish clone M1/70 as an essential tool in immunology for dissecting cell lineage, monitoring inflammatory responses, and blocking integrin-mediated cell functions.

Overview of Clone M1/70 (Anti-CD11b) Dosing Regimens in Mouse Models

Clone M1/70 is a widely used rat monoclonal antibody targeting CD11b (integrin alpha M/Mac-1) in mice, primarily employed for myeloid cell identification, functional blocking, and cell subset characterization in immunology, neuroscience, and cancer research. However, detailed, standardized dosing regimens for in vivo use of M1/70 are not consistently published across vendors or in primary literature, unlike other commonly used antibodies (e.g., anti-PD-1, anti-Ly6G).

Current Knowledge from Available Sources

• General Statement on Variability: Dosing regimens for M1/70 "vary substantially depending on the intended application, mouse strain, and experimental goal," but specific protocols are rarely detailed in vendor literature.
• Lack of Standardized Guidelines: While some vendors offer generalized antibody dosing guides (e.g., for checkpoint inhibitors), there is no comparable, peer-reviewed table for M1/70 in mouse models. Most available dosing information pertains to in vitro assays (e.g., flow cytometry), not in vivo administration.
• Application-Dependent Dosing: The primary documented use of M1/70 is in flow cytometry and functional blocking assays in vitro, where typical concentrations are less than or equal to 0.25 µg per test (for staining 10⁵–10⁸ cells). However, this does not translate directly to in vivo dosing.
• In Vivo Use: Some references mention the potential for in vivo functional assays using "functional grade" M1/70, but do not provide dosing details, schedules, or routes of administration. This suggests that in vivo dosing must be empirically determined by each lab, often based on pilot experiments and literature precedent.
• Comparative Context: For other antibodies (e.g., anti-PD-1, anti-Ly6G), in vivo doses in mice typically range from 100–500 µg per mouse, administered intraperitoneally every 3–4 days, depending on the target and model. However, no such consensus exists for M1/70.

Practical Guidance

• Empirical Titration: Researchers are advised to titrate M1/70 in their specific mouse model to determine the optimal dose for the desired biological effect, whether for cell depletion, functional blocking, or marker detection.
• Consult Literature: Review published studies using M1/70 in your model of interest for dosing precedents. Protocols may vary widely; for example, some studies may use 100–200 µg per mouse for functional blockade, analogous to other myeloid-targeting antibodies, but this is not a formal recommendation.
• Vendor Support: Contact antibody suppliers for application-specific protocols or recommendations, as these are not always provided in product datasheets.
• Route and Schedule: If no published protocol exists, consider starting with routes (e.g., intraperitoneal) and schedules (e.g., every 3–4 days) commonly used for similar antibodies, then adjust based on experimental outcomes.

Summary Table: M1/70 Dosing Information by Application

Key Takeaways

• There is no universal, peer-reviewed dosing regimen for M1/70 in mouse models; protocols are highly model- and application-dependent.
• Most available information is for in vitro use; in vivo dosing must be empirically determined and validated in each experimental context.
• Researchers should seek guidance from published studies in their specific model and consult vendors for protocol support.
• Comparative dosing from similar antibodies may provide a starting point, but should not be assumed effective without validation.

In summary, while M1/70 is a standard tool for myeloid cell identification and functional studies in mice, its in vivo dosing lacks consensus and must be tailored to the specific experimental design and mouse model.