A hemocyte classification scheme for the tunicate Styela plicata

Many classification systems have been developed to identify different types of tunicate hemocytes. However, no one system has used a multi- parameter approach to classify hemocytes from the solitary tunicate Styela plicata. This study provides such a multi-parameter classification scheme for S. plicata hemocytes. Three broad classes of hemocyte encompassing eight individual hemocyte types were identified. Classifications were based on bright and dark field microscopy, as well as immunofluorescence staining and immunohistochemistry using a suite of anti-hemocyte monoclonal antibodies. Flow cytometry was also used to complement the classification system as a rapid method to identify S. plicata hemocyte sub-populations.