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The Uses of BD Fc Block in Immunophenotyping of Mouse or Rat Leukocytes

FcgII and FcgIII low-affinity receptors for complexed IgG (Fc receptors or FcR) are designated CD32 and CD16, respectively, and are expressed on many cell types, including B lymphocytes, NK cells, granulocytes, monocytes, macrophages, and platelets. Some antibody preparations may bind via their Fc portions to FcR-bearing cells, resulting in high "background" staining.

Mouse BD Fc Block is a purified rat IgG2b anti-mouse CD16/CD32 monoclonal antibody (Cat. No. 553141 and 553142),1 while Rat BD Fc Block (Cat. No. 550270 and 550271) is a purified mouse IgG1anti-rat CD32 monoclonal antibody.2 Mouse and Rat BD Fc Block can be used to block the Fc-mediated adherence of antibodies* to mouse and rat FcR, respectively. Furthermore, it has been reported that the Fc domain of the anti-mouse CD16/CD32 mAb 2.4G2 binds the FcgI receptor (CD64) and blocks this additional FcR.1 Since Mouse and Rat BD Fc Block are antigen-specific mAbs, anti-mouse CD16/CD32 and anti-rat CD32, they may also be used as primary staining reagents for detection of mouse and rat FcR-bearing cells, respectively.

Pre-incubation of mouse or rat cell suspensions with the respective BD Fc Block for several minutes, prior to staining with specific antibodies,* assures that any observed staining is due to the interaction of the antigen-binding portion of the antibody with an antigen on the cell surface. The following figures illustrate typical applications of Mouse and Rat BD Fc Block.

Fcblock 1

Fcblock 2

*Experiments using unconjugated rat anti-mouse primary antibodies or mouse anti-rat primary antibodies in the presence of BD Fc Block must be carefully designed. Second-step reagents must be chosen which will not cross-react with BD Fc Block, rat IgG2b or mouse IgG1. BD Biosciences Pharmingen offers a selection of isotype-specific anti-rat and anti-mouse immunoglobulin mAbs which may be used for this purpose.


References:

Unkeless, J.C. 1979. Characterization of a monoclonal antibody directed against mouse macrophage and lymphocyte Fc receptors. J. Exp. Med. 150:580-596.

BD Biosciences Pharmingen. Unpublished results.