Disruption of haemocyte function by exposure to cytochalasin b or nocodazole increases the susceptibility of Galleria mellonella larvae to infection

Abstract

Administration of non-toxic concentrations (10 mM) of cytochalasin b and nocodazole to larvae of Galleria mellonella increased their susceptibility to infection by the yeast Candida albicans. These agents were found to inhibit the process of phagocytosis and to reduce the killing ability of haemocytes. In addition, both cytochalasin b and nocodazole reduced the release of antimicrobial peptides (e.g. apolipophorin 3) and enzymes (e.g. serine protease) from PMA stimulated haemocytes. Rhodamine coupled phalloidin staining revealed reduced F-actin formation in haemocytes treated with nocodazole or cytochalasin b. By disrupting the formation of F-actin cytochalasin b and nocodazole have the ability to retard the function of haemocytes, in the same manner as they affect mammalian neutrophils, and thus increase the susceptibility of larvae to infection. The results presented here demonstrate that haemocytes are sensitive to inhibition by nocodazole and cytochalasin b, in a similar manner to neutrophils, thus highlighting another similarity between both cell types and so increasing the attractiveness of using insects as alternative models to the use of mammals for in vivo pathogen or drug screening.

Galleria mellonellaas a model host to study virulence ofCandida

“…Hemocytes numbers were significantly lower in larvae infected with C. parapsilosis and C. orthopsilosis compared with C. metapsilosis . Correlation of hemocytes numbers with survival after Candida infection has also been observed in other studies 5 , 15 , 31 - 33 and hemocytes function has been clearly linked to the outcome of fungal infections in Galleria 34 , 35 . Gago et al speculated that pseudohyphae production by phagocytosed yeasts may damage hemocytes, thus contributing to the lower number of hemocytes observed.…”

Galleria mellonellalarvae as an infection model for group A streptococcus

“…Although more of the same strains need to be tested in different labs to draw meaningful conclusions, this highlights the potential differences either in wax worms provided by different suppliers, environmental, or experimental conditions. In a recent publication, Banville et al 48 showed that nutritional deprivation led to a reduction in immune response and an increased susceptibility to infection. This does not explain the differences between our study and that conducted by Olsen et al as both our wax worms were starved post-infection.…”

Different forms of apolipophorin III in Galleria mellonella larvae challenged with bacteria and fungi

“…On the other hand, a particulate fraction of the hemolymph apoLp-III could originate from the hemocytes. Secretion of apoLp-III from isolated G. mellonella hemocytes in vitro has been recently reported [4]. Moreover, release of apoLp-III stored in hemocyte granules into hemolymph upon bacterial infection has been described in H. cunea [24].…”