The monoclonal antibody ER-TR9 recognizes murine SIGN-related 1 (SIGN-R1). Mouse SIGN-R1,- a homolog of human DC-SIGN, is a 37 kDa type II transmembrane protein containing a single, C-terminal C-type lectin domain. SIGN-R1 is a specific marker for the identification of macrophage subpopulations present in the marginal zone of spleen (the so-called marginal zone macrophages (MZM)), in the lymph node medulla, and in the peritoneal cavity of some mouse strains. ER-TR9 does not react with macrophages in other regions of the spleen, such as CD169+ marginal metallophils and F4/80+ red pulp macrophages. In the spleen, the MZM function in trapping and clearance of blood-borne microbial antigens. SIGN-R1 mediates the uptake of encapsulated microbes , particularly through the recognition of microbial polysaccharides. Uptake of FITC-labeled dextran by macrophages can be blocked both in vivo and in vitro by the monoclonal antibody ER-TR9. Therefore, the monoclonal antibody ER-TR9 can be used to study the uptake of polysaccharides by macrophages.
Flow cytometry, Frozen sections, Functional studies
FC: Antibody ER-TR9 stains the extracellular domain of SIGN-R1. Peritoneal cells were pre-incubated with anti-CD16/32 to block Fc gamma before staining. As a negative control an isotype-matched antibody was used- (Ref.6)
IHC-F:- Tissue sections were fixed in acetone and stained with antibody ER-TR9 using a two-step immunoperoxidase method (Ref.1).
FS: Antibody ER-TR9- blocked the recognition of- zymosan and C. albicans by peritoneal macrophages. An isotype-matched antibody was used as a negative control. The polysaccharide mannan was used as a positive control. (Ref.4).
For immunohistology and flow cytometry 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 1:50. For blocking studies in vitro, dilutions have to be made according to the amounts of SIGN-R1 to be inactivated.
Peritoneal macrophages of (Ref.4)