Morphological and cytochemical studies of the effects of ecdysteroids in a lepidopteran cell line (IAL-PID2)

Abstract

The Indian meal-moth cell line, IAL-PID2, established from larval wing discs was examined from the 250th to the 300th passages. The cultured cells retain various structural and functional qualities of epidermal cells. Under hormone-free conditions PID2 cells grow as a monolayer of round or spindle-shaped cells. They appear as weakly active epidermal cells. The endoplasmic reticulum and Golgi apparatus are poorly developed and secretory activity is reduced. Culture conditions resulted in considerable cellular expansions, abundance of storage products (glycogen, lipids), and hypertrophy of the lysosomal system. The PID2 cell line retains the ability to respond to ecdysteroids; 20-hydroxyecdysone treatment (2×10-6 M) triggered morphogenetic and secretory processes. Cells formed pseudoepithelial aggregates interconnected and linked by desmosome-like structures. The hormone-stimulated cells are involved in the biosynthesis of N-acetyl-D-glucosamine-rich glycoproteins. The glycosylation sites were located, by use of WGA-gold particles, on cellular expansions and all along the plasma membrane. The possible significance of these glycoproteins is discussed.