An Anti-Mouse CXCR5 Monoclonal Antibody (Cx₅Mab-3) Shows High Affinity for Flow Cytometry

The CXC chemokine receptor 5 (CXCR5) is a member of the G protein-coupled receptor family that is highly expressed in B cells and a subset of T cells such as T follicular helper cells. Various types of cancers, including non-small cell lung cancer, breast cancer, and prostate cancer also express CXCR5; therefore, antibodies that specifically bind to CXCR5 could be useful for clarification of the mechanisms of cancer progression. In this study, we aimed to develop high-affinity monoclonal antibodies (mAbs) for flow cytometry against mouse CXCR5 (mCXCR5). The established anti-mCXCR5 mAb, Cx5Mab-3 (rat IgG2b, kappa), reacted with mCXCR5-overexpressed Chinese hamster ovary (CHO)-K1 (CHO/mCXCR5) by flow cytometry. Kinetic analyses using flow cytometry indicated that the dissociation constants (KD) of Cx5Mab-3 for CHO/mCXCR5 is 7.2 × 10−10 M, indicating that Cx5Mab-3 is useful for detecting mCXCR5 by flow cytometry with high affinity.