Anti-Mouse MAdCAM-1 (MECA-367) - Purified <i>in vivo</i> PLATINUM^TM Functional Grade (M1408-GRP)

MAdCAM-1 is a cell adhesion leukocyte receptor expressed by mucosal venules that helps direct lymphocyte traffic into mucosal tissues and regulates the passage and retention of leukocytes1, 2. MAdCAM-1 binds integrin receptor α4β7 and L-selectin2, 3, 4. Two alternatively spliced isoforms of MAdCAM-1 exist5, both of which are capable of binding α4β72. MECA-367 was generated by immunizing Wister rats with endothelial cells isolated from BALB/c mesenteric and peripheral lymph nodes6. Immunohistological screening of hybridomas yielded two mAbs, MECA-367 and MECA-89, that stain high endothelial venules (HEVs) in mucosal lymphoid organs and Peyer’s patches, but not peripheral lymph nodes (axillary, brachial, popliteal, and inguinal). Immunofluorescence staining of high endothelial cells shows that both MECA-367 and MECA-89 react with antigens on the cell surface. The epitopes for MECA-367 and MECA-89 are distinct. MECA-367 recognizes the N-terminal immunoglobulin domain of MAdCAM-l, and MECA-89 recognizes the second immunoglobulin domain4, 5. MECA-367 inhibits the binding of normal and neoplastic lymphocytes to HEVs in mucosa-associated lymphoid organs and Peyer’s patches6. In contrast, MECA-89 reacts with the same vessels, binds to isolated MECA-367 antigen, but has no effect on lymphocyte binding. In vivo, MECA-367 blocks homing of normal lymphocytes to mucosa-associated lymphoid tissues6. MECA-367 also inhibits α4β7 binding3 and blocks sticking and rolling of preactivated lymph node cells4.