Biotinylated anti-rat primary antibodies are produced by immunizing a host—typically mouse, rabbit, or goat—with a rat-derived antigen, purifying the immunoglobulin by affinity chromatography, and then covalently linking biotin to primary amine groups on the antibody. The resulting conjugate is characterized by its biotin-to-IgG ratio and must be titrated to preserve antigen-binding affinity. A critical distinction exists in the reagent landscape: many products marketed as “biotin anti-rat” are secondary antibodies—anti-rat immunoglobulin reagents raised in another host that detect rat primary antibodies. The primary format discussed here involves the antigen-binding immunoglobulin itself, directly conjugated to biotin. Representative examples include biotinylated anti-rat CD4 (clone W3/25), available in biotin form alongside purified and R-PE conjugates, and biotin anti-rat CD11b/c (clone OX-42), a mouse IgG2a monoclonal raised against rat peritoneal macrophages.

Applications

Biotinylated anti-rat primary antibodies are validated across a broad spectrum of immunoassay platforms. A biotinylated anti-rat GRO-β/MIP-2 polyclonal antibody is documented for Western blot, dot blot, immunohistochemistry, immunofluorescence, immunoprecipitation, flow cytometry, and cell culture, with working concentrations of 0.1–0.2 µg/mL for Western blot and 0.25–1.0 µg/mL for direct and sandwich ELISA. A biotinylated anti-rat Kcnj8 monoclonal antibody (clone S366-60) is validated for immunocytochemistry (1:100), immunofluorescence (1:100), immunohistochemistry on formalin-fixed paraffin-embedded sections, and Western blot (1:1000).

In flow cytometry, the biotin format is particularly valuable because the high-affinity biotin–streptavidin interaction (Kd ≈ 10⁻¹⁵ M) enables stable binding and signal amplification with streptavidin-fluorophore conjugates. Biotin anti-rat CD11b/c (clone OX-42) is quality-tested by immunofluorescent staining with flow cytometric analysis, with a suggested use of ≤0.25 µg per million cells in 100 µL volume, and additional reported applications include immunohistochemistry of acetone-fixed frozen sections, immunoprecipitation, and in vitro and in vivo blocking of C3bi binding. The biotin format also enables magnetic cell separation, in which streptavidin-conjugated magnetic beads capture biotinylated primary antibody-labeled cells.