The monoclonal antibody S5/1 recognizes the human receptor for C5a (CD88). The C5a receptor- is a seven transmembrane GTP-binding-protein-coupled receptor of 45kDa which binds with high affinity to human anaphylatoxin C5a. Upon C5a binding- G-protein-dependent cellular- responses are initiated such as increased intracellular Ca2+, granule fusion with the cell membrane, enzyme release and oxidative burst suggesting that C5aR is an important mediator of inflammation. The C5a receptor is expressed on a broad range of cell types, including- neutrophils, monocytes/macrophages, dendritic cells, astrocytes and microglia.
Interestingly, C5a receptor signalling has been associated with several inflammatory diseases including rheumatoid arthritis.-
Clone S5/1 was raised against a synthetic peptide comprising the N-terminal domain of the C5aR (Met1-Asn31). The antibody has been shown to inhibit the binding of C5a to its receptor.
Flow cytometry, Frozen sections, Functional studies, Paraffin sections, Western blot
FC: Antibody S5/1 stains the N-terminal domain of CD88. 1x106 leukocytes were incubated with 2 µg of antibody (Ref. 1).
FS: Antibody S5/1 inhibits C5a binding to its receptor at a concentration of 3.3 µM (Ref. 2)
IHC-P: Tissue sections were fixed in 2% paraformaldehyde and pretreated with 5% normal rabbit serum before applying antibody S5/1 (Ref. 3).
W: extracts from smooth muscle cells were separated by SDS-PAGE, the observed band size with S5/1 antibody is 42kDa (Ref. 5).
For immunohistology, flow cytometry and Western blotting dilutions to be used depend on detection system applied. It is recommended that users test the reagent and determine their own optimal dilutions. The typical starting working dilution is 1:10. For inhibition of binding of C5a to its receptor dilutions have to be made according to the amounts of C5a to be inhibited.
Whole blood granulocytes