title: Innate immune system still works at diapause, a physiological state of dormancy in insects.
abstract: Diapause is most often observed in insects and is a physiologically dormant state different from other types of dormancy, such as hibernation. It allows insects to survive in harsh environments or extend longevity. In general, larval, pupal, or adult non-diapausing insects possess an innate immune system preventing the invasion of microorganisms into their bodies; however, it is unclear whether this system works under the dormant condition of diapause. We here report the occurrence of innate cellular reactions during diapause using pupae of a giant silkmoth, Samia cynthia pryeri. Scanning electron microscopic analysis demonstrated the presence of two major types of cells in the body fluid isolated from the thoracic region of a pupa. Phagocytosis and encapsulation, characteristics of innate cellular reactions, by these cells were observed when latex beads as foreign targets were microinjected into the internal portion of a pupa. Such behavior by these cells was still observed even when pupae were continuously chilled at 4°C. Our results indicate that innate cellular reactions can work in diapausing insects in a dormant state.
authors.affiliation: Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nakamura
authors.forename: Kenji
authors.initials: K
authors.lastname: Miyado
authors.forename: Youki
authors.initials: Y
authors.lastname: Takezawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Ohnami
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sato
authors.forename: Chihiro
authors.initials: C
authors.lastname: Ono
authors.forename: Yuichirou
authors.initials: Y
authors.lastname: Harada
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yoshida
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kawano
authors.forename: Seiya
authors.initials: S
authors.lastname: Kanai
authors.forename: Mami
authors.initials: M
authors.lastname: Miyado
authors.forename: Akihiro
authors.initials: A
authors.lastname: Umezawa
mesh_terms: D000222:Adaptation, Physiological / Q000276:immunology*; D000818:Animals; D001833:Body Temperature Regulation / Q000276:immunology*; D007113:Immunity, Innate; D008855:Microscopy, Electron, Scanning; D009036:Moths / Q000276:immunology / Q000502:physiology* / Q000648:ultrastructure; D010587:Phagocytosis; D011679:Pupa / Q000276:immunology / Q000502:physiology / Q000648:ultrastructure