Anti-Mouse CD80 (B7-1) [Clone RM80] — Purified in vivo PLATINUM™ Functional Grade

Clone RM80 is a rat monoclonal antibody (IgG2a) specifically targeting mouse CD80 (B7-1), a cell surface glycoprotein crucial for T cell costimulation. Its primary in vivo applications in mice are centered around modulating immune responses by blocking CD80 signaling pathways.

Common In Vivo Applications of RM80 in Mice

CD80 Blockade and Immune Modulation
RM80 is frequently used to block CD80 interaction with its receptors, CD28 and CTLA-4, both in vitro and in vivo. In vivo, this blockade is instrumental in studying the role of CD80 in T cell activation and regulation, as CD80–CD28 interaction stimulates T cell responses, while CD80–CTLA-4 interaction inhibits them. By administering RM80 to mice, researchers can investigate how CD80-mediated costimulation affects immune responses, tolerance, and autoimmunity.

T Cell Activation and Tolerance Studies
Given that CD80 is expressed on antigen-presenting cells like activated dendritic cells, macrophages, and B cells, RM80 allows researchers to assess how inhibiting CD80 alters outcomes such as T cell clonal expansion, cytokine production, and development of immunological tolerance. This is particularly relevant for studying transplantation, autoimmunity, and infectious disease models.

Flow Cytometry and Phenotypic Analysis
Although primarily a functional blockade tool, RM80 is also validated for flow cytometry, enabling researchers to track CD80 expression on immune cell populations before, during, and after in vivo experiments.

Comparison to Similar Antibodies

Other clones, such as 1G10, are also used for in vivo CD80 blockade in mice. The selection between RM80 and alternatives depends on specific validation, availability, and experimental design requirements. Both antibodies are rat IgG2a and suitable for in vivo neutralization, but researchers should confirm clone-specific validation for their models.

Summary Table

In summary, clone RM80 is a well-established tool for in vivo studies of T cell costimulation and immune regulation in mice, especially for investigating the consequences of CD80 blockade on immune responses and disease models.

Commonly used antibodies or proteins that appear in the literature with CD80 (RM80 refers to anti-mouse CD80 antibody, often used as a blocking or detection antibody) include those involved in costimulatory and checkpoint regulation pathways, particularly target molecules that interact with CD80 or modulate T cell responses.

Key molecules and their commonly used experimental antibodies or proteins include:

• CD28: Major ligand on T cells that receives costimulatory signals from CD80. Antibodies against CD28 are routinely used in conjunction with CD80 to study costimulation in T cell activation assays.
• CTLA-4 (CD152): Immune checkpoint receptor that competes with CD28 for CD80 binding, delivering inhibitory signals. Anti-CTLA-4 antibodies are combined with CD80 in blockade or competition assays, or to trace regulatory T cell interactions.
• PD-L1 (CD274): Checkpoint ligand that can also bind and interact with CD80, impacting immune responses. PD-L1 blocking or detection antibodies (such as anti-PD-L1) are commonly paired with CD80 in studies of checkpoint pathways.
• CD86 (B7-2): Closely related to CD80, provides costimulatory signals as another CD28 and CTLA-4 ligand. Anti-CD86 antibodies are frequently used together with CD80 antibodies to assess or block costimulation.
• Fc fusion proteins and engineered fusion therapeutics: These include soluble CD80-Ig or CD80-Fc, as well as dual-activity fusion proteins (e.g., CD80–Fc, CD80–IL-2 or ALPN-202/davoceticept), employed to study or enhance immune responses through combined blockade or costimulation.

In typical experimental or therapeutic settings, combinations frequently include:

• Anti-CD28 and anti-CD80,
• Anti-CTLA-4 and anti-CD80,
• (occasionally) Anti-CD86,
• Anti-PD-L1 and anti-CD80.

Several commercial antibody suppliers (such as R&D Systems and Abcam) offer panels against these targets, enabling combinatorial blocking, activation, or detection schemes.

In summary, the most commonly used antibodies or proteins applied with RM80 (anti-CD80) in research are anti-CD28, anti-CTLA-4, anti-CD86, anti-PD-L1, and engineered fusion proteins like CD80-Fc or CD80-IL-2. These combinations are central to dissecting and manipulating immune costimulatory and checkpoint pathways.

Clone RM80 is primarily referenced in scientific literature as a monoclonal antibody specific for mouse CD45R, widely used to identify and characterize B cells in immunological studies. The key findings from its citations include:

• Identification of B Cells: RM80 has enabled reliable detection and isolation of murine B cells in both flow cytometry and immunohistochemical experiments, facilitating detailed study of B cell populations and their functions in health and disease.
• Characterization of Hematopoietic Stem Cells: It has contributed to research on the purification and quantification of mouse hematopoietic stem cells, supporting foundational studies on stem cell biology, particularly those by Spangrude et al. (Science, 1988).
• Analysis of Immune Cell Subsets: RM80’s specificity for CD45R has allowed immunophenotyping of lymphoid and myeloid cells in various models, including neoplasms, autoimmune conditions, and viral infections. It has been central in studies examining the persistence of activated cytotoxic T lymphocytes and the role of different immune cell subsets in pathological conditions.
• Immunohistochemical Applications: The antibody is routinely used in immunohistochemical analysis of paraffin-embedded tissues, enabling studies of T-cell subsets and leukocyte infiltration in tissues from rodents.
• Research in Diabetes and Autoimmunity: RM80 has been cited in work on non-obese diabetic mouse models to investigate inflammatory infiltrates in the pancreas and their correlation with diabetes development, underlining its utility in autoimmune research.

Across these studies, RM80 has provided a crucial molecular tool for immune cell identification, recovery, and analysis, underpinning major advances in murine immunology and related biomedical research.

Available published data do not comprehensively document the dosing regimens of clone RM80 anti-mouse CD80 antibody across different mouse models, and most sources, including Bio-Rad’s product information, do not specify recommended in vivo dosing ranges. However, related literature and analogous antibody studies provide some reference points for dosing strategies.

Key Points and Context:

• Clone RM80 is a rat IgG2a monoclonal antibody targeting mouse CD80 (B7-1), primarily used to modulate immune responses in murine models.
• Different mouse models (e.g., transplant, infection, or inflammation models) may require tailored dosing regimens to address differences in immune activation or suppression needs.

Regimen Examples from Related Literature:

• High-Risk Corneal Transplant Model: Anti-CD80/86 antibodies (not explicitly RM80, but functionally similar) were administered intraperitoneally. However, the referenced study does not specify the precise dose or frequency for RM80.
• Murine Allogeneic Hepatocyte Rejection Model: Anti-CD80 (and CD86) monoclonal antibodies were administered at 100 mg per day for 5 consecutive days intraperitoneally, starting at the time of hepatocyte transplantation. The antibody isotype and administration route here are similar to RM80, and this regimen is representative of intensive short-course blocking approaches in acute rejection models.

Additional Considerations:

• Regimens are often adapted depending on the:
  • Mouse strain and age
  • Disease/experimental model (e.g., transplant rejection vs. autoimmune disease)
  • Experimental endpoints (e.g., short-term functional blockade vs. chronic modulation)
• Formulation and purity (as per manufacturer): Clone RM80 is supplied as purified IgG in PBS with 0.09% sodium azide; ensure removal of azide if using for in vivo dosing.

Summary of Evidence and Limitations:

• There is no uniform, published standard for clone RM80’s in vivo dosing across models.
• Typical regimens for similar anti-CD80 antibodies range from tens to hundreds of micrograms (up to 100 mg/kg or 100 mg total per animal per dose) administered over several days.
• Selection of dosing regimen should be customized, considering antibody source, intended effect, mouse model specifics, and prior pilot testing for efficacy.

Direct protocol guidance should be sought from published methods sections using clone RM80 or by requesting recommended protocols from the antibody supplier when high experimental fidelity is needed.