Generation of monoclonal antibodies that recognize the planarian intestine and other tissues. (A) Screen strategy. (B) Preimmunization serum (1:200) did not detectably label planarian tissue. (C) Test sera (1:200) ubiquitously labeled planarian tissues, with slightly elevated intestinal labeling. (D) Pie chart depicting the number of clones (n = 384 total) in the primary screen with indicated labeling specificities. (E-X) Examples and schematics of immunolabeling from the primary screen. (E-I) mAbs that label the intestine (schematic, I). (J-N) mAbs that label the nervous system (schematic, N). (O-X) Examples of mAbs that label other non-intestinal tissues (schematics, S and X). Anterior is to the top in all images. Cell and tissue types are indicated in each panel. “CNS”, central nervous system. “VNC”, ventral nerve cord. Scale bars: 100 μm (B, C, E-H, J-M, O, T, U, and W); 50 μm (P-R); 25 μm (V).