Anti-Mouse IFNα (Clone TIF-3C5) – Purified in vivo GOLD™ Functional Grade

Clone TIF-3C5 is a monoclonal antibody used in in vivo mouse studies to specifically neutralize mouse interferon alpha (IFNα), particularly subtypes IFN-αA, -1, -4, -5, -11, and -13, without cross-reacting with mouse IFNβ or IFNγ.

In experimental models, TIF-3C5 is administered—typically via intraperitoneal injection at various doses and schedules—to block the activity of mouse IFNα during immune responses or infection. For example:

• West Nile Virus model: Mice are given TIF-3C5 (commonly 250–500 µg per dose) on schedules such as one day prior, and one and three days after infection. Blocking IFNα with TIF-3C5 leads to increased lethality following West Nile Virus infection, indicating the antibody’s efficacy in neutralizing IFNα and demonstrating the essential antiviral function of endogenous IFNα.
• Functional details: TIF-3C5 has a circulating half-life of about 4 days in mice, providing a useful time frame for blocking experiments.
• Experimental outcomes: Enhanced viral susceptibility and lethality from West Nile Virus infection in wild-type mice treated with TIF-3C5 mirrors the phenotype seen in IFNα pathway knockout mice (e.g., Irf7^-/-^), confirming the antibody’s in vivo neutralization of IFNα.

Essentially, TIF-3C5 is used as a tool to dissect the role of IFNα in antiviral immunity, immune regulation, and disease models by antibody-mediated neutralization in live animals.

Key details:

• Dose and administration: Typical regimens are 250–500 µg per dose, administered intraperitoneally at multiple time points around infection or immune challenge.
• Specificity: Binds only to mouse IFNα and not IFNβ or IFNγ, allowing selective functional blockade of type I IFNα signalling in vivo.

Researchers use TIF-3C5 in vivo to assess the biological and immunological consequences of IFNα blockade in various disease and infection models in mice.

Commonly used antibodies and proteins paired with TIF-3C5 (an anti-mouse IFNα antibody) in the literature include:

• HDβ-4A7 (anti-IFNβ): This monoclonal antibody is frequently used alongside TIF-3C5 to dissect the specific roles of IFNα and IFNβ in murine models, particularly in studies of viral infection and immune modulation. Their selective blockade enables researchers to independently examine the consequences of neutralizing each interferon subtype.
• MAR1-5A3 (anti-IFNAR1): This antibody targets the type I interferon receptor (IFNAR1) and is often used in parallel with TIF-3C5 to block all type I interferon signaling, since IFNAR1 is required for signal transduction of both IFNα and IFNβ. This helps distinguish between the effects of broad type I IFN blockade and more selective inhibition.

Additional proteins and reagents that may be used in combination with TIF-3C5, depending on experimental context:

• Recombinant IFNα subtypes (e.g., IFN-αA, -1, -4, -5, -11, -13) for specificity and neutralization assays.
• Isotype control antibodies, used as negative controls to confirm that observed effects are due to specific antibody blocking.

Summary Table:

The use of these antibodies, particularly HDβ-4A7 and MAR1-5A3, is well-documented in studies investigating the immunological roles of type I interferons in mouse models.

Clone TIF-3C5 is a monoclonal antibody that specifically binds and neutralizes several mouse IFNα subtypes (IFN-αA, -1, -4, -5, -11, and -13), but does not react with mouse IFNβ or IFNγ. Key scientific findings from literature citations of clone TIF-3C5 include:

• Subtype Specificity: TIF-3C5 recognizes a shared epitope among listed mouse IFNα subtypes, with no binding to IFNβ or IFNγ. This allows for selective blockade of IFNα without affecting other type I or type II interferons.

• In Vitro Functional Activity:

  • TIF-3C5 efficiently blocks IFNα-induced Stat1 phosphorylation and the induction of MHC-I (H2-Kb) expression in cell lines (e.g., L929 fibrosarcoma), in a dose-dependent manner.
  • TIF-3C5 neutralizes the antiviral activity of both recombinant and natural IFNα in vitro, as shown by loss of protection in L929 cells infected with vesicular stomatitis virus (VSV) when IFNα signaling is blocked.
  • The blocking efficiency varies between subtypes, e.g., it is highly effective against IFN-α1 at low antibody concentrations (ID${50}$ = 9 ng/well), while much higher doses are needed for IFN-α4 (ID${50}$ = 2000 ng/well).

• In Vivo Activity:

  • TIF-3C5 circulates with a half-life of approximately 4 days in mice.
  • Administration of TIF-3C5 leads to increased mortality in mice infected with West Nile Virus (WNV), mimicking the susceptibility seen in IRF7 knockout mice. This underscores the vital role of IFNα-mediated protection against viral infection.
  • Notably, the increased lethality did not always reach statistical significance depending on the dosing regimen and experimental conditions.

• No Neutralization of IFNβ or IFNγ:

  • TIF-3C5 is highly specific and does not interfere with IFNβ or IFNγ bioactivity, which is critical for experiments aiming to dissect IFNα-specific roles.

• Research Applications:

  • TIF-3C5 is widely used to selectively investigate the biological and immunological roles of mouse IFNα, including studies of antiviral defense, cytokine signaling, and viral pathogenesis.

In summary, the most cited and characterized findings for clone TIF-3C5 are its selective neutralization of multiple murine IFNα subtypes, dose-dependent blockade of IFNα-mediated cellular responses, and its pivotal use in dissecting the functional contributions of IFNα in mouse models of infection and immunity.

Dosing regimens of clone TIF-3C5—an anti-mouse IFNα monoclonal antibody—vary across mouse models and experimental aims, but key parameters commonly adjusted include dose amount, schedule, and route of administration.

Key dosing regimens published:

• In West Nile Virus infection models, TIF-3C5 was administered to wild-type and Ifnb^-/-^ mice by:

  • 500 µg intraperitoneally (i.p.) one day prior and two days following infection (total: 2 doses).
  • As an alternative, 250 µg i.p. one day prior, one day following, and three days following infection (total: 3 doses) significantly increased effect compared to the 2 × 500 µg regimen.
  • Both regimens used i.p. injection and were evaluated for their impact on survival and disease lethality.

• In tumor immunotherapy studies using models such as AE17, AB1, and Renca:

  • 1 mg TIF-3C5 i.p. every third day for three total doses, beginning three days after first administration of immune checkpoint blockade (ICB) antibodies (e.g., anti-PD-1/PD-L1).
  • The schedule was designed for IFNα blockade during ICB response assessment and was standardized across these tumor models.

Additional Context:

• Clone TIF-3C5 specifically recognizes multiple murine IFNα subtypes (αA, α1, α4, α5, α11, α13), but not IFNβ or IFNγ.
• All referenced studies used the intraperitoneal route, but precise timing, doses, and frequency were tailored to infection or tumor model requirements.

Summary Table: TIF-3C5 Dosing Across Mouse Models

These regimens should be further optimized depending on the specific experimental objectives, pharmacokinetics, and target IFNα activity profile in each mouse model.