Anti-Mouse TIM-4 – Purified in vivo PLATINUM™ Functional Grade

Clone RMT4-53 is a widely used rat monoclonal antibody for in vivo applications in mice, primarily to block TIM-4 (T cell immunoglobulin and mucin domain 4) function on antigen-presenting cells.

Key in vivo applications of RMT4-53 in mice include:

• TIM-4 Blockade Studies: RMT4-53 is commonly used to block TIM-4 function in vivo to study the role of TIM-4 in immune responses, particularly its involvement in T-cell co-stimulation, antigen presentation, and the regulation of T cell proliferation.
• Transplantation and Alloimmunity Models: RMT4-53 is employed in models of allogeneic transplantation, such as murine islet transplantation. It has been shown to promote islet graft survival by modulating the recipient’s immune response. Specifically, RMT4-53 treatment can shift the immune response from Th1 (pro-inflammatory) to Th2 (anti-inflammatory), decrease TIM-4⁺ B cells and dendritic cells, and slightly reduce regulatory T cells (Tregs).
• Autoimmune and Inflammatory Disease Research: Blocking TIM-4 with RMT4-53 in vivo is used to dissect the contribution of TIM-4 in various autoimmune and inflammatory processes, given its role in facilitating the phagocytosis of apoptotic cells and acting as a co-stimulatory molecule in immune responses.
• Safety and Mechanism Studies: Many studies use RMT4-53 to clarify the mechanisms by which TIM-4 signals influence the activation and tolerance of T cells, as well as the broader immune cell compartment in mice, including effects on dendritic cells and B cell subsets.

The antibody is typically administered intraperitoneally in mouse models, following dosing regimens optimized for blockade efficiency in the relevant experimental context.

In summary, the most common in vivo applications of Clone RMT4-53 in mice are immune modulation via TIM-4 blockade in models of transplantation, autoimmunity, and inflammation, as well as mechanistic studies on the role of TIM-4 in antigen-presenting cell function and T cell regulation.

Based on the available information, RMT2-25 (Anti-TIM-2) and RMT3-23 (Anti-TIM-3) are commonly used antibodies alongside RMT4-53 in the literature.

Combined Therapeutic Applications

The RMT4-53 antibody has been used in combination strategies to enhance immune responses. Notably, RMT4-53 has been combined with RMT3-23 (anti-TIM-3) to maximize the therapeutic effects of cancer vaccines against B16 melanomas through NK cell and T cell-mediated mechanisms. This synergistic approach demonstrates how blocking multiple TIM family members can enhance antitumor immune responses.

Cancer Therapy Combinations

In cancer immunotherapy studies, RMT4-53 has been used alongside various therapeutic agents, including:

• DNA vaccines or tumor cell vaccines (FVAX) against B16 melanoma
• Chemotherapy agents such as cisplatin or oxaliplatin for colon adenocarcinoma treatment

These combinations leverage TIM-4 blockade to enhance tumor antigen-specific T cell responses and increase the frequencies of IFN-γ-producing CD8+ T cells while inhibiting tumor growth.

Clone RMT4-53 is a monoclonal antibody specific for mouse TIM-4, and its key findings in scientific literature relate primarily to immune modulation, transplantation tolerance, and tumor immunity.

Key Findings from RMT4-53 Citations:

• Immune Skewing and Islet Transplantation:

  • RMT4-53 targeting of TIM-4 prolongs islet graft survival in Th1-mediated alloimmunity in mice, with 30% of islet grafts surviving long-term after administration.
  • Treatment with RMT4-53 leads to a shift from a Th1 to Th2 immune response, as evidenced by an increased Th2/Th1 ratio and higher anti-donor IL-4 production without a concomitant increase in IFN-γ.
  • There is a notable decrease in TIM-4^+ B cells and dendritic cells following RMT4-53 treatment, indicating that the antibody can modulate immune cell populations responsible for graft rejection.
  • In Th2 (or Th17)-biased models, RMT4-53 actually accelerates islet rejection, and this effect is also seen in B-cell-depleted mice, indicating context-dependent effects of TIM-4 blockade.

• Tumor Immunology:

  • RMT4-53 and analogous anti-TIM-4 antibodies have been studied for their ability to modulate tumor immune responses.
  • TIM-4 blockade using such antibodies can enhance the anti-tumor effects of immunogenic chemotherapy in mouse models, and combination therapy (TIM-4 blockade + anti-PD-1) further improves survival in tumor-bearing mice.
  • One mechanism involves increased infiltration and activity of IFN-γ-producing CD8^+ T cells in the tumor microenvironment, which correlates with tumor growth inhibition.

• Specificity and Use as Positive Control:

  • RMT4-53 binds tightly to murine TIM-4 but does not bind human TIM-4, making it a standard positive control in studies validating anti-mouse TIM-4 antibody efficacy.

• Mechanistic Insights:

  • The antibody is a functional grade reagent used to block the immunomodulatory activity of TIM-4, particularly its role in phagocytosis (clearance of apoptotic cells).
  • TIM-4 blockade does not significantly alter many other myeloid or T-cell populations in certain tumor models, suggesting selectivity in its action.

Summary Table: Main Mechanistic and Functional Findings

In conclusion: clone RMT4-53 is a widely used tool to probe TIM-4 function in murine models, revealing context-dependent roles in both promoting transplantation tolerance and enhancing anti-tumor immune responses by modulating Th1/Th2 balance and cytotoxic T cell activity.

Dosing regimens for clone RMT4-53 (anti-mouse TIM-4) vary depending on the mouse model, experimental context, and disease application. The most detailed dosing strategies are reported for immune modulation in transplant, liver injury, and cancer models.

Reported Dosing Regimens by Model

• Islet Transplantation/Alloimmune Response Models
  In C57BL/6 mice receiving BALB/c islet grafts, a main regimen is:

  • 500 μg intraperitoneally (i.p.) on day 0, then
  • 250 μg i.p. on days 2, 4, 6, 8, and 10 after transplantation.This regimen is used both in wild-type and genetically modified recipients (such as Tbet−/− mice and B cell–depleted mice).
    Dosing adjustments were not reported between these mouse lines; thus, the total antibody amount and timing remained consistent across these models.

• Liver Ischemia–Reperfusion Injury Models
  In studies of acute liver injury, treatment was:

  • 0.25 mg (250 μg) intravenous (i.v.), administered at either 48 hours or 2 hours prior to the onset of ischemia.This reflects adaptation to the acute timeline of ischemia–reperfusion experiments, with single dosing closely aligned to the insult.

• Cancer and Graft Models (General Blockade)
  In skin graft models and certain cancer immunotherapy contexts, dosing is often described more generally:

  • Dosing schedules of 200–250 μg per injection every 4th day (i.p.), for three or more doses are reported in combination studies and for monotherapy blockade applications.
  • Other sources mention enhanced conversion of CD4^+^ T cells into induced Tregs with similar regimens, although the precise schedule may vary by study.

Summary Table: Dosing Regimens for RMT4-53 in Mouse Models

Additional Notes

• Route of Administration: Both intraperitoneal (i.p.) and intravenous (i.v.) injections are used, with i.p. being more common in immunological and transplantation studies, and i.v. for acute injury models.
• Total Cumulative Dose: For transplantation models, mice typically receive a cumulative dose of up to 2 mg over 10 days.
• Model-Specific Adjustments: No evidence was found in these summaries of substantial regimen changes between mouse strains (e.g., wild-type vs. knockout) within a given model. In most cases, dosing is standardized for model consistency.

In summary:
Clone RMT4-53 is commonly dosed at 200–500 μg per injection, given i.p. or i.v., with frequency and timing tailored to the disease model: multiple doses over a post-operative window for transplantation, or one/two doses timed to injury in acute models. Regimens are typically consistent across different genetic backgrounds unless otherwise experimentally justified.