Growing bacteria shed elicitors of Drosophila humoral immunity
(English)Article in journal (Refereed) Submitted
Peptidoglycan (PGN) is a well-characterized cell wall component from bacteria that is recognized by Peptidoglycan Recognition Receptors (PGRPs) in the Drosophila immune system. It has long been a forum of debate how the immune system is able to recognize this elicitor since the PGN is hidden by the outer membrane in gram-negative bacteria and by teichoic acids in gram-positive bacteria. We show here that bacteria separated from Drosophila S2 cells by a semi permeable membrane are able to up-regulate the Imd pathway. Studies with supernatants from exponentially growning bacterial cultures show that bacteria shed elicitors in sufficient amounts to potentially induce the Imd pathway. However, when employing supernatants from bacteria in stationary phase, no stimulatory effect of the Imd pathway was detected. The elicitor effect was much reduced when the supernatans was treated with the N-acetylmuramoyl-Lalanine amidase M.mPGRP-L, which is a known scavenger of PGN. Our studies therefore indicate that bacteria in growth phase shed elicitors of PGN nature that can induce a humoral immune response in Drosophila S2 cells.
IdentifiersURN: urn:nbn:se:su:diva-29783OAI: oai:DiVA.org:su-29783DiVA: diva2:235348