The role of gill podocytes in the recognition of non-self in the crayfish, procambarus clarkII.
Crayfish chromatography indicates that the gills are the primary
organ for removal of foreign substances from the circulation of the
crayfish. The epithelial podocytes lining the gill sinuses appear to
play a major role in clearance of fluorescently labeled latex beads. For
all gill podocytes examined, 25% exibited binding of fluorescent latex
beads. In contrast, hemocytes remaining in the gills after
chromotography consistently had less than 5% positive cells binding the
latex beads. Circulating hemocytes are not required for the clearance
process. Circulating eosinophilic granulocytes, however, are able to
bind and phagocytize non-self substances in vitro. Eosinophilic
granulocytes also migrate into areas of tissue that have been injured.
The circulating prohemocytes appear to be the source of these
granulocytes. They differentiate into granulocytes during the
inflammatory response. Thus, the circulating hemocytes appear to play a
secondary function in destruction of non-self, after initial clearance
of non-self from the circulation by the gill tissues.