Anti-Mouse MAdCAM-1 (MECA-367) – Purified in vivo PLATINUM^TM Functional Grade

Clone MECA-367 is an anti-mouse MAdCAM-1 monoclonal antibody commonly used in in vivo applications in mice to neutralize MAdCAM-1, thereby preventing lymphocytes, particularly those expressing α4β7 integrin (LPAM-1) and CD62L, from tethering, rolling, and homing to gut-associated lymphoid tissues such as Peyer's patches and mesenteric lymph nodes. This antibody is utilized to study and modulate the homing of lymphocytes to these tissues, which is crucial for understanding inflammatory conditions like Crohn's disease.

Key in vivo applications include:

• Blocking lymphocyte homing: MECA-367 blocks the interaction of MAdCAM-1 with its counter-receptor, preventing lymphocytes from migrating to intestinal tissues.
• Inflammatory disease models: It is used to study the role of MAdCAM-1 in inflammatory conditions by preventing the recruitment of lymphocytes to inflamed tissues.
• Pharmacodynamic studies: MECA-367 is applied to enhance the understanding of pharmacokinetic/pharmacodynamic relationships in the context of targeting MAdCAM-1.

Commonly used antibodies or proteins in the literature with MECA-367 (an anti-MAdCAM-1 monoclonal antibody) include isotype controls (such as rat IgG2a, e.g., R35–95), other adhesion molecules like VCAM-1, and proteins or antibodies associated with lymphocyte homing, including PF-00547659 (an anti-human MAdCAM-1 antibody), as well as markers such as LPAM-1 (α4β7 integrin) and CD62L (L-selectin).

Key antibodies or proteins used with MECA-367:

• Isotype controls: Frequently, rat IgG2a (e.g., R35–95) is used as a nonbinding immunoglobulin control to distinguish specific from nonspecific binding effects.
• PF-00547659: This is a humanized anti-MAdCAM-1 antibody often used for cross-species comparison of anti-MAdCAM-1 effects in pharmacological and mechanistic studies.
• VCAM-1 (Vascular Cell Adhesion Molecule 1): Both as a comparator in homing and adhesion studies, and as a marker for other adhesion pathways.
• Integrins and adhesion markers: Studies frequently examine LPAM-1 (α4β7 integrin), VLA-4 (α4β1 integrin), and CD62L (L-selectin) due to their roles in lymphocyte trafficking and interaction with MAdCAM-1.
• Other controls: Mouse IgG3-FITC, IgG1-PE, and other isotype-labeled controls are regularly used when multicolor flow cytometry is performed.

These combinations enable researchers to dissect the role of MAdCAM-1 in immune cell trafficking, validate antibody specificity, and control for non-specific effects in both in vivo and in vitro experiments.

Key Findings from MECA-367 Scientific Literature Citations

MECA-367 is a well-characterized rat monoclonal antibody targeting murine mucosal addressin cell adhesion molecule-1 (MAdCAM-1). Its citations in the literature have contributed significantly to understanding the physiological and pathological roles of MAdCAM-1, particularly in lymphocyte trafficking and inflammatory disease models.

Functional Role and Mechanism

• Blockade of MAdCAM-1/α4β7 Interaction: MECA-367 specifically inhibits the binding of MAdCAM-1 to its counter-receptor, the leukocyte integrin α4β7 (LPAM-1), both in vitro and in vivo, thereby preventing lymphocyte homing to gut-associated lymphoid tissues, such as Peyer’s patches and inflamed intestinal mucosa.
• Affinity and Specificity: MECA-367 binds with high affinity to mouse MAdCAM-1 ((K_d = 5.1) pmol·L(^{-1})) and effectively blocks leukocyte adhesion to MAdCAM-1-expressing endothelium in functional assays.
• Domain Specificity: The antibody recognizes and binds to the first domain of MAdCAM-1, which is critical for ligand-receptor interaction.

Effects in Experimental Models

• Inhibition of Lymphocyte Recruitment: In several preclinical models of colitis, MECA-367 treatment reduced lymphocyte recruitment to the intestine, diminished mucosal destruction, and alleviated clinical signs of inflammatory bowel disease (IBD).
• Impact on Effector T-Cell Populations: MECA-367 induces a dose-dependent increase in circulating β7+ memory T-cells without affecting β7− populations, consistent with a specific blockade of MAdCAM-1-dependent homing.
• Modulation of Disease: Administration of MECA-367 has been shown to reduce diabetes development in a T cell transfer model, suggesting a broader role for MAdCAM-1 in autoimmune pathogenesis.

Scientific and Translational Significance

• Biomarker Development: The pharmacological effects of MECA-367 have been used to identify biomarkers for the activity of anti-MAdCAM-1 therapies in higher species and humans, aiding translational research.
• Tool for Pathophysiological Studies: MECA-367 has been instrumental in elucidating the role of MAdCAM-1 in lymphocyte trafficking and in establishing the importance of the α4β7/MAdCAM-1 axis in mucosal immunity and chronic inflammation.
• Scope of Applications: Beyond functional studies, MECA-367 is widely used in techniques such as flow cytometry, immunohistochemistry, Western blot, and immunoprecipitation to detect and quantify MAdCAM-1 expression.

Summary Table: Key Functional Outcomes of MECA-367

Conclusion

MECA-367 is a critical tool for studying MAdCAM-1 biology, demonstrating that blockade of the MAdCAM-1/α4β7 axis prevents lymphocyte homing to mucosal tissues, reduces inflammation in models of IBD, and modulates autoimmune responses. Its use has advanced both basic research and the development of therapeutic strategies targeting this pathway in human disease.

Dosing regimens for clone MECA-367 in mouse models most often involve single intravenous (IV) injections at increasing doses, typically ranging from 0.1, 0.3, 1, to 3 mg·kg⁻¹. The optimal effect on target cell populations (e.g., an increase in circulating β7⁺ or LPAM⁺ memory T-cells) is generally observed around 1 mg·kg⁻¹, with higher doses sometimes used for dose–response evaluation.

Essential details and context:

• Mouse strain: Studies have been reported using FVB mice, with each dose evaluated in groups (n = 8 per cohort).
• Route of administration: Intravenous tail vein injection is standard; the antibody is delivered in saline, typically around 20 µL per mouse.
• Timing: Assessment of pharmacodynamic effects (e.g., changes in circulating T-cell subsets) is commonly performed 3 to 7 days post-dose.
• Controls: An isotype control antibody (e.g., rat IgG₂) is used for baseline comparison.

Comparison across mouse models:

• Dose range (0.1–3 mg·kg⁻¹ IV) and timing (single dose, 3–7 days post-administration) are typical for MECA-367 across studies.
• Variation in strain or disease model (e.g., inflammation vs. homeostasis) may affect immune cell dynamics and downstream outcomes, but baseline dosing regimens remain similar, focusing on single-dose escalation.
• Other dosing routes or schedules for MECA-367 in mice are not widely reported, differing from some other antibodies which are sometimes administered by repeated doses or other methods.

Additional notes:

• The primary effect monitored is displacement of high-affinity LPAM⁺ memory T-cells from MAdCAM-1 interactions, confirmed by flow cytometry.
• Biomarker assays developed in mice have been applied in preclinical models for translation to non-human primates and eventual human studies.
• MECA-367 is a rat monoclonal antibody specific for mouse MAdCAM-1, and its functional blockade is a key tool in studies of immune migration and gut-associated lymphoid tissue.

In summary, dosing regimens of clone MECA-367 are consistent across mouse models, characterized by single IV injection of escalating doses (0.1–3 mg·kg⁻¹), mostly evaluated at 1 mg·kg⁻¹, with immune readouts 3–7 days post-dose. Published data do not indicate substantial variation in regimen by mouse strain or disease context, though downstream effects may differ due to biological variables between models.