Establishment of a Novel Anti-Mouse CCR1 Monoclonal Antibody C 1 Mab-6.

C-C motif chemokine receptor 1 (CCR1/CD191) is a member of G-protein-coupled receptors and is expressed on myeloid cells, such as neutrophils and macrophages. Because the CCR1 signaling promotes tumor expansion in the tumor microenvironment (TME), the modification of TME is an effective strategy for cancer therapy. Although CCR1 is an attractive target for solid tumors and hematological malignancies, therapeutic agents for CCR1 have not been approved. Here, we established a novel anti-mouse CCR1 (mCCR1) monoclonal antibody (mAb), C 1 Mab-6 (rat IgG 2b , kappa), using the Cell-Based Immunization and Screening method. Flow cytometry and Western blot analyses showed that C 1 Mab-6 recognizes mCCR1 specifically. The dissociation constant of C 1 Mab-6 for mCCR1-overexpressed Chinese hamster ovary-K1 was determined as 3.9 × 10 -9 M, indicating that C 1 Mab-6 possesses a high affinity to mCCR1. These results suggest that C 1 Mab-6 could be a useful tool for targeting mCCR1 in preclinical mouse models.