The AFS98-CP131 monoclonal antibody is a chimeric version of the original AFS98 antibody. The variable domain sequences are identical to the original AFS98 but the constant region sequences have been switched from rat IgG2a to mouse IgG2a. The AFS98-CP131 antibody contains no Fc mutations just as the original rat IgG2a antibody does not. The AFS98-CP131 monoclonal antibody reacts with mouse colony stimulating factor 1 receptor (CSF1R), also known as macrophage colony-stimulating factor receptor (M-CSFR), and CD115. CSF1R is a single-pass type I membrane protein and member of the platelet-derived growth factor receptor family. In mice CSF1R is expressed by monocytes/macrophages, peritoneal exudate cells, plasmacytoid and conventional dendritic cells, and osteoclasts. CSF1R is a receptor for CSF1 and CSF1 signaling through CSF1R regulates the proliferation and differentiation of cells in the monocytic lineage. The AFS98 antibody has been reported to deplete macrophages and block CSFR1 in vivo.

See the references for the original rat IgG2a AFS98 antibody (https://bioxcell.com/catalogsearch/result/?q=BP0213).