Monoclonal antibodies to mouse butyrylcholinesterase

► We present the first monoclonal antibodies against mouse BChE, cross-reacting with dog and one of them with rat BChE. ► Antibodies recognize different epitopes which could enable double sandwich ELISA. ► Antibodies capture mouse BChE from different tissues. ► Immunohistochemistry of tissue section can replace more problematic activity staining. ► We propose an efficient way to purify mouse BChE from small amount of biological sample. Our immunization strategy introduced recombinant mouse butyrylcholinesterase (BChE) to naïve BChE knockout mice. An extraordinarily strong immune reaction gave rise to a whole spectrum of antibodies with different properties. Two selective and highly efficient monoclonal anti-mouse BChE antibodies 4H1 (IgG1) and 4C9 (IgG2a), with Kd values in the nanomolar range were generated. ELISA detected BChE in as little as 20–50nl of mouse plasma using 2μg (4H1) or 4μg (4C9). Both antibodies cross-reacted with BChE in dog plasma but only 4H1 reacted with rat BChE, suggesting that the antibodies are targeted towards different epitopes. Surprisingly, neither recognized human BChE. The anti-mouse BChE antibodies were used in immunohistochemistry analysis of mouse muscle where they specifically stained the neuromuscular junction. The antibodies enable visualization of the BChE protein in the mouse tissue, thus complementing activity assays. They can be used to study a long-lasting question about the existence of mixed acetylcholinesterase/BChE oligomers in mouse tissues. Moreover, monoclonal anti-mouse BChE antibodies can provide a simple, fast and efficient way to purify mouse BChE from small amounts of starting material by using a single-step immunomagnetic bead-based protocol.