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

Clone RMT4-53 is a rat monoclonal antibody that targets mouse TIM-4 and is commonly used in vivo to block TIM-4 signaling in mice. The principal in vivo applications include investigating immune modulation, particularly in transplantation, autoimmunity, and cancer.

Key in vivo applications:

• TIM-4 Blockade in Immune Regulation Studies:
  RMT4-53 is primarily used to block TIM-4, a receptor found on antigen-presenting cells, to dissect its functional role in modulating immune responses. This application is central to studies investigating how TIM-4 regulates T cell activation, proliferation, and costimulation.

• Transplantation Models:
  RMT4-53 has been used to study its effect on alloimmune responses in murine transplantation models. For example, in islet transplantation, in vivo targeting of TIM-4 with RMT4-53 led to prolonged islet graft survival and shifted the immune response from a Th1- to a Th2-type (anti-inflammatory). This was associated with reduced splenic TIM-4+ B cells and dendritic cells, suggesting possible depletion or modulation of these populations.

• Tumor Immunity and Cancer Therapy:
  In cancer research, RMT4-53 is used to block TIM-4 in studies aimed at enhancing anti-tumor immunity, sometimes in combination with other immunotherapies such as anti-PD-1 agents. By targeting TIM-4, researchers seek to disrupt immunosuppressive signaling in the tumor microenvironment.

• Autoimmunity and Inflammation:
  Studies use RMT4-53 to explore the role of TIM-4 in autoimmune models and inflammation, given its effects on T cell activation and polarization.

• Cell Depletion and Functional Modulation:
  In vivo administration of RMT4-53 can reduce the number of TIM-4+ immune cells (e.g., B cells and dendritic cells), possibly through antibody-mediated depletion.

Additional technical notes:

• RMT4-53 is used at function-blocking doses, with dosing regimens tailored to specific experimental protocols (e.g., repeated intraperitoneal injections for transplant models).
• While the antibody is also used for in vitro assays and immunofluorescence, its major cited in vivo use is blocking TIM-4 function to study its physiological roles.

In summary, the most common in vivo applications of clone RMT4-53 in mice are for blocking TIM-4 to study immune mechanisms in transplantation tolerance, tumor immunity, and autoimmunity, often by altering antigen-presenting cell and T cell functions.

Commonly used antibodies or proteins with RMT4-53 in the literature include other monoclonal antibodies targeting the TIM family (such as anti-TIM-1, anti-TIM-2, and anti-TIM-3), anti-PD-1, isotype controls, and functional proteins involved in immunological assays.

Key antibodies and proteins frequently used alongside RMT4-53:

• Anti-TIM-1 antibody (clone RMT1-17): Used for comparative or combination studies addressing distinct members of the TIM family.
• Anti-TIM-2 antibodies (clones RMT2-14 and RMT2-26): Frequently selected to dissect the overlapping and non-overlapping roles of TIM proteins in immune regulation.
• Anti-TIM-3 antibody (clone RMT3-23): Included when broader TIM family modulation is investigated.
• Anti-PD-1 antibody (clone Rmp1-14): Co-administered in checkpoint inhibition and tumor immunology studies, often to assess synergistic effects with TIM-4 blockade.
• Isotype controls: Typically, rat IgG2b isotype control or anti-keyhole limpet hemocyanin controls are used to ensure specificity of the antibody effect in experimental settings.
• TGFβ (Transforming Growth Factor Beta): Used in the induction of regulatory T cells (iTregs) in functional assays testing the effect of TIM-4 blockade.
• Antigenic proteins or fusion constructs: For example, bm12 skin or splenocyte antigens in alloantigen-specific Treg suppression assays, and mouse TIM-4-Ig fusion protein as immunogen for generating antibodies.

Experimental models often also employ:

• Thy1.1 and Thy1.2 surface marker antibodies: For congenic tracking in adoptive transfer and immune tolerance studies.
• Foxp3-GFP reporter mice or protein constructs: For identifying and sorting regulatory T cell populations in mechanistic studies on immune tolerance.

In summary, the literature commonly utilizes a combination of TIM family antibodies (TIM-1, TIM-2, TIM-3), checkpoint inhibitors (anti-PD-1), isotype controls, and proteins for regulatory T cell induction and immune cell tracking in conjunction with RMT4-53 for comprehensive analysis of immune regulation and therapeutic strategies.

Key findings from clone RMT4-53, as cited in scientific literature, indicate that it is a monoclonal antibody specifically targeting mouse TIM-4 (T cell immunoglobulin and mucin domain 4), with broad relevance in transplantation immunology and tumor immunity research.

Major findings:

• Alloimmune Response in Islet Transplantation:
  RMT4-53 administration in a murine model promotes islet graft survival by skewing the immune response toward a Th2 phenotype (increased Th2/Th1 ratio). Key immunological effects include:

  • Decreased TIM-4+ B cells and dendritic cells post-transplantation.
  • Increase in IL-4-producing (Th2) cells, but not IFN-γ-producing (Th1) cells.
  • No significant changes in Th17 or effector CD4+ T cells, but a reduction in Treg percentages in treated mice.
  • In Th2-biased settings (Tbet-deficient mice), RMT4-53 unexpectedly accelerated islet rejection, suggesting context-dependent effects of TIM-4 blockade.
  • In B-cell-depleted mice, RMT4-53 prompted islet rejection, highlighting B cell involvement in TIM-4-mediated tolerance.

• Immune Modulation in Tumor Contexts:
  RMT4-53 is used as a benchmark for mouse TIM-4 blockade in characterizing new antibodies and investigating TIM-4 function in tumor immunity. In these settings:

  • RMT4-53 binds tightly to mouse TIM-4, with no cross-reactivity for human TIM-4; this specificity is often used as a control.
  • TIM-4 blockade, using RMT4-53 or analogous antibodies, may enhance antitumor immunity and synergize with immune checkpoint inhibitors, although most combination studies now employ more translational antibodies.
  • In mouse xenograft models, TIM-4 blockade does not significantly alter myeloid or T lymphocyte composition in the spleen, supporting a primary effect on antigen presentation and phagocytosis rather than broad lymphocyte depletion.

• Mechanistic Insights:

  • TIM-4 is a phosphatidylserine receptor, involved in apoptotic cell recognition and clearance, primarily expressed by myeloid cells including dendritic cells.
  • RMT4-53’s targeting of TIM-4 leads to immunomodulation largely through changing myeloid activity and antigen processing, with downstream effects on adaptive immune skewing and graft outcomes.
  • RMT4-53 is species-specific and does not bind human TIM-4, meaning its findings are limited to mouse models but define key mechanisms relevant for downstream human antibody development and translational research.

In summary, clone RMT4-53 is extensively used to demonstrate the role of TIM-4 in immune regulation, particularly in transplantation tolerance, Th2 polarization, and myeloid cell function in mice. It is a critical tool for dissecting myeloid-mediated immune modulation and informs the design of next-generation anti-TIM-4 therapeutics for both transplantation and tumor immunology.

Dosing regimens of clone RMT4-53 (anti-mouse TIM-4 antibody) vary depending on the mouse model and disease context, with most published regimens involving repeat intraperitoneal or intravenous injections at defined intervals and doses tailored to the specific experimental setup.

Key Dosing Schedules Across Mouse Models:

• Th1-Mediated Islet Transplant Model (C57BL/6 mice with BALB/c islet graft):

  • 500 μg intraperitoneal (i.p.) on day 0
  • 250 μg i.p. on days 2, 4, 6, 8, and 10
  • This regimen significantly prolonged graft survival and reduced TIM-4+ B cells and dendritic cells.

• Th2 (and Th17) Response Model (Tbet^−/−​ C57BL/6 mice with BALB/c islets):

  • Apparent use of a similar schedule, but the antibody in this context accelerated graft rejection rather than prolonging survival.

• B-cell–Depleted Recipients:

  • RMT4-53 treatment (same general dosing as above) promoted islet rejection in B-cell–depleted C57BL/6 mice, showing model-specific effects.

• Liver Ischemia Model:

  • 0.25 mg (250 μg) per mouse intravenously (i.v.) administered either 48 hours or 2 hours before ischemia.

• Tumor Immunotherapy / Combination Studies:

  • 200 μg per injection, intraperitoneally, every 4 days for three doses in combination experiments with other agents.

• Skin Graft Models:

  • Although dosing is not always specified, RMT4-53 has been used to promote regulatory T cell induction in vivo; details for these models can sometimes mirror those above or be adjusted by investigators.

Summary Table:

Important Context and Considerations:

• The total dose, intervals, and route of administration (i.p. vs i.v.) are adjusted based on the disease model, anticipated mechanism of action, and pharmacokinetics in the mouse strain used.
• RMT4-53 has variable effects depending on the immunological context (e.g., prolongs graft survival in Th1 settings but accelerates rejection in Th2).
• In transplantation and tumor models, repeated dosing (rather than single bolus) is typical to maintain blockade during critical phases of immune response.
• Reports sometimes extrapolate between models; precise dose and schedule optimization requires consideration of the specific experimental objectives and controls.

If you need the dosing regimen for a particular disease area or genetically modified mouse line not covered above, specifying that context may help refine the answer.