Teratocytes and Host/Parasitoid Interactions

Teratocytes, derived from extraembryonic tissues of parasitic Braconidae, Platygasteridae, and Scelionidae, play several important roles in parasitoid-host interactions. Teratocytes have trophic, immunosuppressive, and secretory functions but their specific activities depend upon the life stage of the host, the time spent by the parasitoid within the host, and the individual species of parasite and host. Teratocytes have immunosuppressive, trophic, and secretory functions. Teratocytes from the braconid, Microplitis croceipes, were obtained at various times from the hemolymph of its host, Heliothis virescens, or from preparations obtained from M. croceipes eggs hatched in vitro. The teratocytes were viewed using scanning electron microscopy and were found to possess a dense coat of microvilli. In vitro cultures of teratocytes secrete proteins and these teratocyte secretory products, when injected into H. virestens larvae, produce many of the same developmental abnormalities observed when larvae are injected with intact teratocytes or are truly parasitized. Finally, it was demonstrated that DNA from the M. croceipes polydnavirus hybridizes with DNA extracted from teratocytes and various other tissues of M. croceipes. Potential implications of the teratocyte/host/polydnavirus interactions are discussed with respect to biological control applications. (C) 1991 Academic Press, Inc.