Cx ₂ Mab-5: A Novel Anti-Mouse CXCR2 Monoclonal Antibody Developed by N-Terminus Peptide Immunization for Multiple Applications

The CXC chemokine receptor 2 (CXCR2) is a member of the G-protein-coupled receptor superfamily and regulates a diverse range of immune responses and tumor progression. CXCR2 is expressed on immune cells, especially neutrophils, and is involved in various immune responses by interacting with its chemokine ligands. Therefore, the development of sensitive monoclonal antibodies (mAbs) for CXCR2 has been desired for treatment and diagnosis. This study established a novel sensitive anti-mouse CXCR2 (mCXCR2) mAb; Cx₂Mab-5 (rat IgG_2a, κ), using the mCXCR2 synthetic N-terminus peptide immunization method. In flow cytometry, Cx₂Mab-5 recognized mCXCR2-overexpressed Chinese hamster ovary-K1 cells (CHO/mCXCR2) and WEHI-3B (murine myelomonocytic leukemia cell) cells, which express endogenous mCXCR2. Cx₂Mab-5 did not cross-react with other mouse CC, CXC, CX3C, and XC chemokine receptors. Cx₂Mab-5 showed a moderate binding affinity for both CHO/mCXCR2 and WEHI-3B. Furthermore, Cx₂Mab-5 detected mCXCR2 in Western blot and immunohistochemistry in CHO/mCXCR2 cells, but a commercially available anti-mCXCR2 mAb (clone SA045E1) did not. Hence, Cx₂Mab-5 can be a valuable tool for analyzing mCXCR2-positive cells in mouse tissues.