Anti-Mouse CD134 (Clone OX-86) – Purified in vivo PLATINUM™ Functional Grade

Clone OX-86 is a monoclonal antibody that targets mouse OX40 (CD134), acting as an agonist to stimulate the OX40 pathway. Common in vivo applications of clone OX-86 in mice include:

• Enhancing T Cell Responses: OX-86 stimulates the OX40 pathway, which is crucial for enhancing T cell clonal expansion and cytokine production. This is particularly beneficial in immunotherapy strategies aiming to boost immune responses against pathogens or tumors.

• Modulating Immune Regulation: By activating the OX40 pathway, OX-86 can influence the balance between effector and regulatory T cells, potentially affecting immune tolerance and autoimmunity.

• Cancer Research: The agonistic effects of OX-86 have been used to delay tumor growth in mice by enhancing the generation of antigen-specific effector T cells and preventing T cell tolerance.

• Vaccine Efficacy Studies: OX-86 can be used to study the immune response to vaccines by augmenting the proliferation of antigen-reactive T cells, thereby improving vaccine efficacy.

Commonly Used Antibodies and Proteins with OX-86 in the Literature

OX-86 is a well-established monoclonal antibody against mouse CD134 (OX40/TNFRSF4), primarily used for studying T cell activation, immune checkpoint modulation, and the dynamics of OX40 signaling in various immunological contexts. In published studies, OX-86 is often used in combination with other antibodies and proteins to provide a comprehensive profile of T cell function, activation status, and immune regulation.

Key Antibodies Commonly Used with OX-86

Commonly Used Proteins

• OX40L-fusion proteins: These include engineered proteins such as MBL-OX40L and Fc-scOX40L, which directly bind OX40 (CD134) and are used in functional assays to verify OX40-binding specificity and activate OX40 signaling pathways.
• FcγRIIb and FcγRIII proteins: These are relevant in understanding the effector function and in vivo activity of OX-86, as the rat IgG1 isotype of OX-86 interacts with mouse FcγRIIb and FcγRIII receptors, influencing its agonistic or regulatory effects.

Application Context

• Flow Cytometry: OX-86 is often combined with antibodies like anti-CD4 and anti-CD25 to phenotype activated T cells, regulatory T cells, and memory T cells.
• Cytokine Detection (ELISA, ICS): Used with antibodies against IFN-γ, IL-2, IL-4, and IL-17A to assess the effector functions of T cells following OX-86 stimulation or CD134 engagement.
• Functional Assays: OX40L-fusion proteins are used to activate or block OX40 signaling, often compared with OX-86 in dose-dependent binding studies to confirm receptor specificity.
• In Vivo Studies: OX-86 is used alongside isotype controls to evaluate therapeutic effects in mouse models of cancer and autoimmunity.

Conclusion

OX-86 is most frequently used in concert with antibodies targeting key cytokines (IFN-γ, IL-2, IL-4, IL-17A), T cell markers (CD4, CD25), and the OX40 ligand (CD252). Fusion proteins (e.g., OX40L-fusion constructs) and Fc receptor proteins are also used to probe the biology of the OX40 signaling axis in functional assays. This multi-parameter approach enables researchers to dissect complex T cell responses in the context of OX40 engagement.

Clone OX-86 is a monoclonal antibody targeting murine CD134 (OX-40, TNFRSF4) that has generated significant findings across immunology and cancer research. This antibody acts as an agonist, stimulating OX-40 signaling and has been extensively used to investigate T cell responses and anti-tumor immunity.

T Cell Costimulation and Cytokine Production

OX-86 demonstrates potent costimulatory effects on T cells when combined with TCR/CD3 stimulation. Studies show that OX-86 significantly increases IL-2 and IFN-γ production from both CD4+ and CD8+ T cells in a dose-dependent manner. This costimulatory activity enhances T cell proliferation and cytokine secretion, suggesting that OX-40 signaling amplifies the immune response beyond primary TCR activation alone.

Role in T Cell Memory Formation

When CD134 is bound by its corresponding ligand (OX-40L) or agonistic antibodies like OX-86, an optimal T cell response is generated that plays a significant role in determining the amount of memory T cells remaining after the immune response. In vivo treatment with OX-86 has been shown to strongly enhance the generation of antigen-specific effector T cells and prevent the induction of T cell tolerance. This finding has important implications for vaccine development and immunotherapy strategies.

Anti-Tumor Activity

Research demonstrates that OX-86 can delay tumor growth in vivo. However, the mechanism appears complex—treatment with activating in vivo antibodies against CD134 enhanced tumor growth in some contexts, suggesting that CD134 functions as an important tumor suppressor, and its absence disrupts the immune response to tumors. The anti-tumor effects likely depend on the specific tumor microenvironment and the balance of immune cell populations present.

NK Cell Enhancement

Beyond T cells, OX-86 engagement enhances natural killer (NK) cell function. Studies show that CD134 engagement on NK cells with an agonistic antibody increased antibody-dependent cellular cytotoxicity (ADCC) capacity and IFNγ secretion. This finding expands the therapeutic potential of OX-40 targeting beyond conventional T cell responses.

Isotype-Dependent Mechanisms

The biological activity of OX-86 varies significantly based on its isotype. The original rat IgG1 version interacts primarily with FcγRIIb and FcγRIII, giving it a low activatory-to-inhibitory FcγR binding ratio and the capacity for direct agonism through FcγRIIb-mediated crosslinking. In contrast, chimeric versions with mouse IgG2a constant regions interact strongly with all activatory FcγR and likely mediate effects through cellular depletion mechanisms rather than pure agonism.

Dosing regimens of clone OX-86 (anti-mouse OX40 mAb) vary by mouse model and experimental aim, commonly ranging from 10 µg to 250 µg per injection, with schedules from a single dose to repeated daily or weekly injections.

• Syngeneic Tumor Models: For the CT26 colon carcinoma model, 100 µg of OX-86 is administered twice per week. This dose has been shown to activate immune responses and alter tumor growth dynamics.
• Regulatory T Cell Studies: Naïve foxp3gfp reporter mice typically receive 0.25 mg (250 µg) intraperitoneally (i.p.) for 3 to 7 consecutive days to study impacts on Treg expansion and memory T cell generation.
• Combined Immunotherapy: In combination regimens (e.g., with anti-CTLA4 and anti-CD137), doses as low as 10 µg or 30 µg per injection are used biweekly or at set intervals; 10 µg in triple-therapy showed efficacy with minimal toxicity, while higher frequencies (e.g., 5–6 injections of 30 µg) can cause treatment-related deaths in certain models like MC38.
• Weight-Based Dosing: Some protocols use weight-adjusted dosing, such as 5 mg/kg, reflecting variation adapted for animal size and experimental goals.
• General Guidance: Manufacturer and supplier protocols support dosing regimens between 10–250 µg/injection, emphasizing the need to tailor dose and frequency to the studied model and endpoint.

Toxicity and reaction risks increase at higher doses and more frequent administrations, including potential anaphylaxis with repetitive dosing.

Summary table:

In conclusion, the OX-86 clone dosing regimen is highly context-dependent, with lower doses favored for combination therapies to minimize toxicity, and higher/frequent doses used for robust immune activation or mechanistic endpoints. Reviewing individual study protocols and monitoring for adverse reactions, especially at higher frequencies or doses, is recommended.