Overview of a scalable procedure to select recombinant mouse monoclonal antibodies. Purified ectodomain fragments of zebrafish cell surface and secreted proteins expressed in mammalian cells were normalized, pooled and used to immunize mice. Hybridomas were generated by cell fusion, and supernatants screened for positives using ELISA. The rearranged light and heavy antibody chains were amplified from RNA extracted from small numbers of hybridoma cells by reverse transcription-polymerase chain reaction and cloned into a single expression plasmid. The recombinant monoclonal antibodies were produced by transfecting mammalian cells before testing for fixation sensitivity and wholemount staining.