The localization of arylphorin in an insect, Calpodes ethlius

Antibodies to arylphorin from Calpodes haemolymph have been used to locate arylphorin by secondary immunogold labelling on electron microscope tissue sections. Arylphorin was found in the secretory pathway (rough endoplasmic reticulum, Golgi complex, secretory vesicles) of the fat body, epidermis, midgut and pericardial cells, as well as in the haemolymph and lymph spaces of reticular systems on the basal haemolymph surfaces of these cells. Binding of anti-arylphorin antibodies also occurred in the epicuticle of the integument and in the reticular cuticle of tracheae, presumably as a result of previous apical epidermal secretion. These results confirm previous observations which showed that arylphorin is synthesized and secreted into the medium in which fat body, epidermis, midgut and pericardial cells have been cultured.