Clone LB21 is a mouse monoclonal antibody specific to the human gene, CR2, or Complement C3d receptor 2. Another name for the gene is CD21. Suppliers have reported additional species reactivites for the target of this clone, including bovine, feline, goat, and sheep. Indicated applications for antibody clone LB21 include immunohistochemistry, flow cytometry, immunofluorescence, and immunoprecipitation.