Isolation of a vascular cell wall-specific monoclonal antibody recognizinga cell polarity by using a phage display subtraction method

Using a strategy consisting of (i) the isolation of cell walls from synchro nously differentiating cells of Zinnia, (ii) the generation of mAbs with an antibody phage display method, and (iii) screening with a subtraction meth od, we isolated mAbs recognizing vascular development-specific cell wall co mponents without prior antigen identification. One of the isolated mAbs, de signated CN 8, recognized a cell wall component contained in the hemicellul osic fraction. Immunohistochemical analyses showed that the CN 8 epitope wa s localized to the cell wall of immature tracheary elements and xylem paren chyma cells. In immature tracheary elements, the CN 8 epitope had a polariz ed localization pattern regardless of whether the cells are formed as parts of vessels in situ or as single tracheary elements in vitro, suggesting th at cell polarity autonomously formed on the cell wall may function in trach eary element differentiation.