Anti-Mouse CD137 (4-1BB) [Clone 3H3] — Purified in vivo GOLD™ Functional Grade

Clone 3H3 is used in in vivo mouse studies primarily as an agonistic monoclonal antibody targeting CD137 (4-1BB). This antibody is known for its strong agonistic activity on CD137, which plays a role in immune system modulation. In studies, 3H3 has been shown to:

1. Induce Immune Activation: It significantly expands CD8+ T cells in the liver and increases the frequency of PD1+TIGIT+ T cells in the spleen and liver, indicating broad T cell activation and potential exhaustion.

2. Enhance Proinflammatory Cytokine Production: Treatment with 3H3 leads to increased systemic proinflammatory cytokines and enhanced T cell infiltration and activation/exhaustion in the liver and spleen.

3. Cause Liver Toxicity: The use of 3H3 in mice can lead to liver toxicity, as evidenced by elevated ALT levels, which is thought to be influenced by the antibody's Fc region binding to activating and inhibitory Fc receptors.

4. Differ from Other CD137 Agonists: Compared to other agonists like CTX-471, 3H3 induces more pronounced immune system changes but may have a narrower therapeutic window due to its potent agonistic activity.

Clone 3H3 is also sold as an in vivo grade recombinant anti-mouse CD137 antibody, suitable for use in in vivo mouse studies.

In contrast, a different clone named 3H3 is used for targeting sodium/hydrogen exchanger 3 (NHE3) in research, primarily for applications such as Western blotting, immunohistochemistry, and immunoprecipitation. However, the context of the query indicates that the focus is on the CD137-targeting clone.

The correct storage temperature for the sterile packaged clone 3H3 antibody (for example, Sigma Aldrich product MABN1813, anti-sodium/hydrogen exchanger 3, clone 3H3) should follow the manufacturer's instructions. According to the product listing, this antibody is shipped at ambient temperature, but the detailed recommended storage temperature is not explicitly given in the search results.

For most purified monoclonal antibodies (including sterile packaged antibodies), standard practice is to store them at 2–8?°C (refrigerated) for short- to medium-term storage to maintain stability, unless otherwise specified in the product data sheet. Certain antibodies may tolerate storage at ambient temperature for shipping, but long-term storage is almost always recommended at refrigeration temperatures to maintain integrity.

If the product datasheet is unavailable, or if you are using a different supplier or different clone, the best practice is:

• Store the sterile packaged clone 3H3 at 2–8?°C.
• Avoid repeated freeze-thaw cycles, as these can degrade the antibody.
• Do not store at room temperature for extended periods unless specifically instructed.

For all sterile supplies, including sterile packaged antibodies, facility guidelines (e.g., The Joint Commission, ASHRAE, NFPA 99) emphasize storing supplies in a clean, well-ventilated area, protected from temperature and humidity extremes, and following the manufacturer's instructions for storage.

If you have the product label or datasheet, verify the specific storage requirements recommended by the manufacturer, as this detail will always take precedence over general guidelines.

Other commonly used antibodies and proteins studied alongside 3H3 (an agonistic anti-4-1BB/CD137 antibody) in the literature include LOB12.3 (another anti-4-1BB antibody), PD-1, and TIGIT, particularly in immunological studies exploring co-stimulatory and checkpoint pathways.

Key examples from the literature:

• LOB12.3: Frequently compared with 3H3 to study differences in T cell activation, isotype effects, and Fc? receptor dependency. Experiments often use various engineered forms (e.g., IgG1, IgG2a) of both antibodies to assess their activity with or without Fc?R crosslinking.
• PD-1 and TIGIT: These immune checkpoint proteins are commonly analyzed via flow cytometry as markers on T cells in studies that investigate the immunomodulatory effects of 3H3. For example, 3H3 treatment has been shown to increase PD-1^+ and TIGIT^+ T cell frequencies, which are associated with T cell activation or exhaustion in tumor settings.
• CD8, CD4, and antigen-presenting cell markers: Experiments typically include antibodies against CD8 (cytotoxic T cells), CD4 (helper T cells), and markers for other immune cell types to profile the response to 3H3, especially when evaluating in vitro co-stimulation assays or in vivo phenotypic shifts.

Less commonly, studies may use other antibodies related to checkpoint molecules (e.g., anti-CTLA-4), and proteins such as agonists or cytokines in combination or comparative settings, but LOB12.3 and checkpoint markers (PD-1, TIGIT) are the most consistently referenced in conjunction with 3H3 in published research.

Clone 3H3 appears in multiple distinct research contexts across different scientific domains, with each representing different biological entities and research applications