Anti-Mouse/Human TYRP1/TRP1 (Clone TA99) – Purified in vivo GOLD™ Functional Grade

Clone TA-99 is a monoclonal antibody widely used in in vivo mouse studies—primarily for targeting the melanoma antigen TYRP1 (gp75) in mouse models of melanoma, especially the B16 and B16-F10 murine melanoma cell lines.

• Tumor Targeting and Localization: When injected into tumor-bearing mice, TA-99 rapidly and specifically localizes to tumor nodules. Fluorescently labeled TA-99 can be visualized within the cytoplasm of tumor cells and within tumor-infiltrating macrophages.
• Therapeutic Studies: TA-99 is used to prevent the outgrowth of melanoma lung metastases in vivo. Mice treated with TA-99 show reduced or absent pulmonary metastases after intravenous B16-F10 cell challenge, demonstrating its antitumor efficacy in an Fc receptor engagement-dependent manner.
• Mechanistic Research: TA-99 enhances CD8+ T cell responses against the target antigen (TYRP1) in tumor-bearing mice, indicating its role in improving anti-tumor immunity beyond direct tumor cell killing.
• Combination Therapy: TA-99 has been tested in combination with other therapeutics, such as MEK inhibitors and immune checkpoint blockade, to improve therapeutic outcomes in tumor-bearing mice.
• Modeling Human Immunotherapy: In mouse models engineered to tolerate human IgG1 (so-called knock-in mice), TA-99 variants with human constant regions are used for chronic dosing and to study long-term treatment efficacy and immunogenicity of Fc-engineered antibodies in vivo, since these mice do not generate strong anti-human antibody responses.
• Other Immune Effects: TA-99 is also noted to induce neutrophil recruitment to tumor sites in addition to its effects on adaptive immunity.

Summary Table: Key Uses of Clone TA-99 in In Vivo Mouse Studies

TA-99 remains a keystone antibody for experimental murine melanoma studies, due to its specificity for TYRP1, in vivo efficacy, and utility in modeling both immune mechanisms and anti-melanoma therapies.

The correct storage temperature for sterile packaged clone TA-99 (Anti-TYRP1 antibody) is 2–8?°C (refrigerated) for short-term storage, typically up to 1 month or 3 months depending on the supplier. For long-term storage, it should be aliquoted and stored at ?20?°C.

• Short-term (up to 1–3 months): Store at 2–8?°C (standard refrigerator temperature).
• Long-term: Aliquot (divide into working volumes to avoid repeated freeze-thaw cycles) and store at ?20?°C.

Always refer to the specific supplier’s recommendation listed on the product data sheet, as buffer composition and formulation (e.g., with/without azide, presence of preservatives) may influence recommended temperatures.

Maintaining sterile integrity also requires undamaged packaging; compromised packaging may render the contents non-sterile, regardless of temperature.

TA99 is frequently used in combination with several other antibodies, proteins, and immunotherapeutic agents in the literature, particularly in melanoma research. Some of the commonly used combinations include:

• DNA vaccines targeting melanosomal antigens: TA99 is often combined with Tyrp1 (TYRP1) DNA vaccination and with gp100 DNA vaccination (gp100 is another melanoma antigen). These combinations aim to broaden the immune response by inducing CD8+ T cell responses against multiple melanosomal targets.
• Adoptive T cell transfer: TA99 has been used together with adoptive T cell therapy and DNA vaccination for enhanced anti-tumor effects.
• Immune checkpoint blockade: TA99 is used in conjunction with immune checkpoint inhibitors (such as anti-PD-1 or anti-CTLA4 antibodies), and in melanoma models, it is sometimes paired with these agents to improve therapeutic efficacy.
• Toll-like receptor (TLR) ligands and cytokines (e.g., IL-2): TA99 combinations with immunostimulatory molecules—particularly IL-2 and TLR ligands—leverage coordinated innate and adaptive immune responses, boosting anti-tumor immunity.
• Agonist antibodies to 4-1BB (CD137): These antibodies activate T and NK cells and are shown to synergize with TA99 to enhance anti-tumor effects. The use of anti-4-1BB with TA99 facilitates both cellular activation and prevents activation-induced cell death.
• Antibody-cytokine fusion proteins: Fusion proteins like TA99-TNF (tumor necrosis factor attached to TA99) have been tested to increase the potency of antibody therapy.
• MEK inhibitors (MEKi): Pharmacological inhibitor combinations, such as MEK inhibitors with TA99 and immune checkpoint blockade, are employed to further improve outcomes in mouse melanoma models.
• Other monoclonal antibodies against tumor antigens: Although not always used directly with TA99, antibodies like anti-CD20 (rituximab), anti-HER2 (trastuzumab), anti-EGFR (cetuximab) are mentioned in the context of similar combination strategies in cancer immunotherapy.

The most commonly reported combinations with TA99 focus on broadening tumor antigen recognition (gp100), enhancing adaptive immune activation (IL-2, 4-1BB agonists), and integrating established immunotherapeutic strategies (immune checkpoint blockade, MEK inhibitors). These combinations are designed to address tumor resistance mechanisms and promote durable anti-tumor immunity.

Clone TA-99 is a widely cited mouse monoclonal antibody targeting tyrosinase-related protein 1 (TRP1), a 75kDa glycoprotein expressed by pigmented melanoma cells. Key findings from scientific literature referencing TA-99 center on its use as a differentiation marker for melanocytes and melanoma, its role in tumor immunotherapy studies, and its utility for immunological characterization.

Essential findings from TA-99 citations:

• Target Specificity and Applications: TA-99 reacts specifically with TRP1/gp75, a pigmentation-associated antigen, and is used for immunocytochemistry, immunohistochemistry, immunoprecipitation, and Western blot analysis to study melanocyte differentiation and melanoma biology.

• Immunotherapy Research: TA-99 serves as a model antibody for preclinical melanoma immunotherapy studies. For example, engineered variants (such as the Fc-optimized TA99-GAALIE) enhance therapeutic efficacy through improved engagement of activating Fc? receptors in mouse models. Fc modifications also alter immunogenicity and clearance, underscoring TA-99’s importance in evaluating antibody engineering strategies for cancer treatment.

• Tolerance and Efficacy Assessment: In genetically modified murine models expressing human IgG1, TA-99 helps determine the effects of chronic antibody exposure, immunogenicity of Fc-engineered variants, and antibody persistence in vivo. For instance, in knock-in mice lacking endogenous anti-human IgG1 responses, TA-99-based therapy was shown to prevent melanoma metastasis more effectively and persist at therapeutic levels compared to control mice.

• Immunocytokine Platform: Conjugates of TA-99 (e.g., TA99-IL2 immunocytokines) have been investigated for tumor-targeted delivery of cytokines. Surprisingly, antigen specificity was not always critical for efficacy, as tumor-specific TA99-IL2 and non-specific immunocytokines could achieve similar anti-tumor effects, suggesting additional factors contributed to therapeutic outcomes beyond simple antigen targeting.

• Developmental History: TA-99 was developed by immunizing mice with human melanoma cells, making it one of the foundational reagents for melanoma immunology.

Additional notes:

• TA-99 is reactive with both mouse and human TRP1, making it useful for comparative studies across species.
• The antibody remains a standard in studies of pigmentation and melanoma differentiation due to its specificity for TRP1/gp75.

These findings collectively highlight TA-99’s crucial role as a research tool for melanoma biology, antibody engineering, and preclinical therapeutic studies.