Surface molecules of extracellular vesicles secreted by the helminth pathogen Fasciola hepatica direct their internalisation by host cells
Fig 8
Host antiserum enhances internalisation of F. hepatica EVs by macrophages.
(A) Immunogenicity of F. hepatica EVs in F. hepatica-infected rats. Equal amounts (10μg total protein) of 15k and 120k EVs were analysed by Western blot using pre-infection (PI) sera and serum samples taken 7, 21 and 70 days post-infection. (B) RAW264.7 macrophages were incubated with PKH26-labelled 120k EVs for 3 h at 37°C and the cells were analysed by confocal microscopy. EVs pre-incubated with pre-infection rat serum were internalised by the macrophages as shown by the punctate red fluorescence observed throughout the cytoplasm. However, when EVs were pre-treated with 21-day rat serum the internalisation the EVs increased considerably. A similar, but less dramatic, effect was observed when EVs were pre-treated with the 70-day serum. Nuclei were stained with DAPI (blue). (C) These effects were statistically significant when measured as fluorescence intensity relative to cells treated with EVs pre-incubated with pre-infection serum.