Anti-Mouse CD3ε [Clone 145-2C11] F(ab’)2 fragment — Purified in vivo GOLD™ Functional Grade

Clone 145-2C11 is widely used in in vivo mouse studies primarily for depletion or functional modulation of T cells by targeting the CD3? chain of the TCR/CD3 complex. When administered to mice, it can activate or delete T cells depending on the study design, dose, and antibody format.

Key applications in vivo include:

• T cell depletion: 145-2C11 effectively removes T cells from circulation, a method employed to assess T cell-dependent processes or to induce immunosuppression in transplant and autoimmune models.
• T cell activation: Binding of 145-2C11 crosslinks the CD3/TCR complex, leading to strong T cell activation, proliferation, and cytokine release ("cytokine storm"). This is used to model T cell responses or to test immunomodulatory therapies.
• Cytokine release and immunosuppression: In mice, 145-2C11 triggers a rapid release of cytokines such as TNF, IFN?, and IL-6, resembling effects observed with anti-human CD3 antibodies in clinical contexts.
• Induction of apoptosis in thymocytes: The antibody can promote apoptosis of immature thymocytes, contributing to immune modulation.
• Downregulation of the TCR complex: 145-2C11 causes rapid internalization and downregulation of surface TCR/CD3, altering T cell receptor signaling and function.

Antibody format matters for in vivo use. For example, recombinant and murinized forms (such as IgG2a) are engineered to enhance efficacy and reduce immunogenicity or adverse reactions. Endotoxin-free, azide-free purified forms (e.g., Ultra-LEAF™ or InvivoFit™) are recommended to minimize confounding inflammation.

In summary, clone 145-2C11 is a central tool for T cell manipulation in mouse models—enabling T cell depletion, functional activation, and immunosuppressive protocols through targeted engagement or removal of the CD3?-positive T cell compartment.

The correct storage temperature for clone 145-2C11, in its typical sterile packaged format, is between 2°C and 8°C (refrigerated conditions), and it must not be frozen. The product should also be protected from prolonged exposure to light to maintain stability. The antibody may be supplied in phosphate-buffered solution with sodium azide, but the key storage recommendations remain consistent: refrigerate, do not freeze, and keep in the dark.

Commonly used antibodies or proteins with 145-2C11 (an anti-mouse CD3 monoclonal antibody) in the literature include:

• Concanavalin A (Con A): Often used as a positive control for T cell proliferation assays alongside 145-2C11 to assess T cell activation and responsiveness.
• Glucocorticoids (e.g., methylprednisolone): High doses of glucocorticoids are administered before 145-2C11 to inhibit systemic cytokine release and attenuate cytokine release syndrome in mouse models.
• PLP139–151 peptide: Used to induce EAE (experimental autoimmune encephalomyelitis) in mice for studies examining immunoregulation by 145-2C11; the antibody is used to modulate disease alongside this peptide.
• Trucount beads: Utilized in flow cytometry for absolute quantification of T cell subsets after 145-2C11 treatment.
• Fc-modified antibodies (e.g., 2C11-Novi): Engineered variants of 145-2C11 to study effects of Fc receptor engagement and immunoregulatory mechanisms in comparison to the original clone.

Other frequently co-used reagents or markers:

• TGF-?: Levels measured in serum by ELISA to assess immunomodulatory effects following 145-2C11 administration.
• Flow cytometry antibodies: Various clones targeting specific surface proteins (e.g., CD4, CD8) are used concurrently to analyze T cell populations impacted by 145-2C11.

In summary, practical combinations often include T cell subset markers, activation agents (Con A), regulatory peptides (PLP), immunosuppressive drugs (methylprednisolone), quantification tools (Trucount beads), and engineered antibody variants for comparative studies.

Key Findings from Clone 145-2C11 in Scientific Literature

Clone 145-2C11 is a hamster monoclonal antibody targeting mouse CD3?, widely used in immunology research to study T cell biology in murine models. The following summarize the most significant findings and applications reported in the literature.

Mechanism of Action and Biological Effects

• T Cell Activation and Proliferation: 145-2C11 potently induces T cell activation by cross-linking the CD3-TCR complex, leading to robust proliferation, cytokine production, and upregulation of activation markers (e.g., CD69, CD25). In vivo, this activation is associated with a rapid and almost complete downregulation of surface TCR on CD4+ T cells, followed by full recovery within five days post-treatment.
• Apoptosis and T Cell Depletion: 145-2C11 induces apoptosis in immature thymocytes and, in vivo, causes significant T cell depletion, likely through activation-induced cell death (AICD). This effect is mediated partly via Fc?R-binding, which enhances cross-linking and apoptosis compared to Fc-modified variants (e.g., 2C11-Novi).
• Cytokine Release: Administration of 145-2C11 triggers systemic cytokine release (e.g., TNF, IFN?, IL-6), which is associated with transient side effects such as body weight loss in mice.
• Immunoregulatory Effects: The antibody increases systemic levels of TGF-?, a key tolerogenic cytokine, likely due to phagocytic clearance of apoptotic T cells.

Experimental Applications

• In Vitro Studies: 145-2C11 is used for T cell activation, proliferation, and cytokine production assays, as well as blocking cytotoxic T lymphocyte (CTL)-mediated cell lysis. It is also effective for complement-mediated cytotoxicity assays, immunoprecipitation, and immunofluorescent staining.
• In Vivo Applications: 145-2C11 is employed for in vivo T cell depletion and stimulation, making it a staple tool for studies of T cell function, autoimmune disease models, and tolerance induction in mice.
• Biochemical and Histological Use: The antibody is suitable for Western blot, immunohistochemistry (on acetone-fixed frozen and zinc-fixed paraffin-embedded sections), and flow cytometry.

Comparative Findings

• Species Specificity: 145-2C11 targets mouse CD3? and is not active in humans, limiting its direct translational use but making it indispensable in murine models of human diseases.
• Comparison with Modified Clones: Compared to Fc-modified anti-CD3 antibodies (e.g., 2C11-Novi), 145-2C11 induces more potent T cell activation, cytokine release, and AICD due to its ability to engage Fc? receptors. The kinetics of TCR downregulation and recovery also differ, with 145-2C11-treated mice showing a faster return to baseline TCR expression.
• Dosage Effects: While effective at relatively low doses, 145-2C11 can induce cytokine release syndrome-like symptoms (e.g., body weight loss) in mice, which contrasts with modified clones that may have reduced side effects.

Limitations and Cautions

• Not for Formalin-Fixed Samples: 145-2C11 is not recommended for formalin-fixed tissues, though it works well on certain other fixed preparations.
• Clinical Translation: While invaluable for mechanistic studies, data from 145-2C11 in mice cannot directly predict the maximum tolerated dose or safety profile of anti-CD3 therapies in humans.

Summary Table

Conclusion

Clone 145-2C11 is a foundational tool in mouse immunology, enabling researchers to dissect T cell activation, apoptosis, depletion, and immunoregulation in vivo and in vitro. Its potent effects on T cell biology have made it essential for modeling human diseases and testing immunotherapies in mice, though its clinical relevance is limited to preclinical studies due to species specificity and differences in the cytokine response compared to humans.