Anti-Mouse IFNAR-1 [Clone MAR1-5A3] — Purified in vivo PLATINUM™ Functional Grade

Clone MAR1-5A3 is widely used in in vivo mouse studies for several key applications:

1. Blocking Type I Interferon Signaling: The antibody is used to transiently block type I interferon (IFN) receptor signaling by targeting the IFNAR-1 subunit of the mouse interferon alpha/beta receptor.

2. Viral Infection Modeling: MAR1-5A3 is particularly valuable for creating more permissive infection models, allowing researchers to study various viral infections, such as those caused by flaviviruses (e.g., dengue and Zika viruses), while maintaining other aspects of immune function.

3. Evaluating Vaccines and Antiviral Strategies: The antibody facilitates high-throughput evaluation of next-generation vaccines and antiviral interventions by creating models that mimic severe infections, enabling more effective pre-clinical testing.

4. Maternal-Fetal Transmission Studies: MAR1-5A3 is used to study transplacental transmission of viruses like Zika, allowing researchers to assess maternal-fetal transmission dynamics and vaccine efficacy in pregnant mice.

5. Cancer and Immune Response Research: Given its role in blocking type I IFN-induced antitumor responses, MAR1-5A3 can also be used to explore the complex interactions between type I interferons and tumor development.

In terms of dosing, common regimens include a single intraperitoneal dose of 2 mg for adult wild-type mice to achieve receptor saturation, with lower doses used in specific experimental contexts.

Commonly used antibodies and proteins alongside MAR1-5A3 (anti-mouse IFNAR-1) in the literature include control antibodies, isotype controls, and antibodies that target other interferons, notably anti-IFN-γ and anti-IFN-β monoclonals such as TIF-3C5 and HDβ-4A7. Researchers typically include these to dissect roles of various interferons in immune responses.

Key examples include:

• TIF-3C5: monoclonal antibody targeting mouse IFN-γ to block IFN-γ responses.
• HDβ-4A7: monoclonal antibody targeting mouse IFN-β for selective blockade.
• GIR-208: used as an isotype control for MAR1-5A3.
• 2H2 (IgG2a): used as an isotype control in experiments with other mouse monoclonal antibodies.
• PIP: another isotype control cited in interferon signaling blockade experiments.

Additional commonly co-used markers and antibodies for flow cytometry and immunophenotyping in experimental setups (particularly when studying T cell responses or immune checkpoint molecules) include those recognizing:

• CD8β
• PD-1 (programmed death receptor-1)
• CTLA-4
• CD44
• CD127
• CD11a
• CD43
  These are typically used to assess the phenotype and functional status of immune cell populations following MAR1-5A3-mediated neutralization.

In summary, alongside MAR1-5A3, the literature frequently uses:

• Anti-IFN-γ (e.g., TIF-3C5)
• Anti-IFN-β (e.g., HDβ-4A7)
• Isotype controls (e.g., GIR-208, PIP, 2H2)
• Flow cytometry markers (CD8β, PD-1, CTLA-4, CD44, CD127, CD11a, CD43) for detailed immunophenotyping.

Clone MAR1-5A3 is a monoclonal antibody widely cited in scientific literature for its role as a highly specific and potent blocker of mouse type I interferon receptor subunit 1 (IFNAR1), enabling transient inhibition of type I interferon signaling both in vitro and in vivo. The key findings from its citations span immunology, infectious disease, and vaccine research.

Key Findings:

• Translational Tool for IFN-I Signaling: MAR1-5A3 is essential for dissecting the role of type I interferons in antiviral and autoimmune responses by effectively inhibiting IFNAR1-dependent signaling.
• Permissive Infection Models: Pre-treatment with MAR1-5A3 increases susceptibility of mice to a variety of viral infections (e.g., flaviviruses like dengue, Zika, West Nile), as it blunts IFN-mediated antiviral defenses, thereby creating robust models for studying pathogenesis and testing vaccines or antivirals. Increased viral replication, altered disease outcomes, and differences in neuroinvasion have been reported in MAR1-5A3-treated animals depending on virus strain, dose, age, and infection route.
• Refinement of In Vivo Protocols: Dosing regimens (typically 0.2–2 mg/mouse via intraperitoneal injection) must be customized according to animal age, strain, pregnancy status, and viral context, as differences affect antibody half-life (1.8–5.2 days) and biological response.
• No Efficient Blood-Brain Barrier Crossing: MAR1-5A3 does not readily cross the blood–brain barrier, so enhanced neurovirulence in models is generally due to viral factors rather than direct central nervous system antibody action.
• Enhanced Pre-clinical Evaluation: By transiently and reversibly suppressing innate immunity, MAR1-5A3 allows more natural (wild-type) mouse strains to be used in high-throughput, pre-clinical vaccine and therapeutic testing against viruses that otherwise would not efficiently replicate in immunocompetent mice.
• Autoimmunity and Inflammatory Disease Models: In autoimmune disease (e.g., lupus) models, MAR1-5A3 ameliorates disease features by dampening type I IFN–driven inflammation, demonstrating the pathological importance of this pathway.
• Validated Across Platforms: MAR1-5A3 is effective in neutralizing IFNAR1 both in vitro (cell culture) and in vivo (animal models) and is used for diverse applications, including flow cytometry, Western blotting, and functional assays of immune modulation.

Summary Table: MAR1-5A3 Major Research Uses and Findings

In essence, MAR1-5A3 is a foundational reagent for transiently manipulating type I interferon signaling in mice, which has revealed critical antiviral, immunomodulatory, and pathological functions of this pathway across numerous fields of biomedical research.

Dosing regimens for the clone MAR1-5A3, a monoclonal antibody that blocks mouse IFNAR-1, vary widely across different mouse models based on factors such as experimental goals, mouse age, and the model's specific requirements. Here are some key variations:

1. Dose Range: The typical intraperitoneal dose of MAR1-5A3 ranges from 0.2 mg to 2 mg per mouse. For example, a dose of 2 mg is commonly used in studies involving wild-type mice to block type I interferon signaling effectively.

2. Experimental Goals:

   • Viral Infection Models: In models of viral infections like flaviviruses (e.g., Zika, West Nile, and dengue viruses), doses such as 2 mg are used to enhance viral replication and study disease pathogenesis.
   • Transplacental Transmission: Lower doses (e.g., 0.2 mg or 1 mg) are used in studies of Zika virus transplacental transmission to observe effects on fetal development.

3. Mouse Age and Strain:

   • Different mouse strains and ages may require adjustments in dosing. For instance, younger mice might require lower doses compared to adult mice.
   • The effectiveness of the antibody can be influenced by the genetic background of the mouse strains used, such as C57BL/6J.

4. Administration Frequency:

   • For sustained in vivo blocking, a loading dose followed by maintenance doses is recommended. For example, a loading dose of 2.5 mg could be followed by weekly doses of 0.5 mg per mouse to maintain receptor saturation.

5. Route of Administration:

   • While intraperitoneal (i.p.) injection is common, other routes like intravenous could be considered for altering biodistribution, though they may have volume limitations.