Table 2.

Vaccination with helminth extracellular vesicles (EVs).

Species	Vaccination method used	Results	Antibodies	Reference
Heligmosomoides polygyrus (nematode)	C57BL/6 mice vaccinated 3 times with EVs + alum i.p.	Vaccination decreased worm burden by 82%.	Exosomes elicited IgM, IgG1, IgA and IgE isotypes reactive with EVs. Mice vaccinated with HES or HES supernatant also generated EV-responsive IgM. Sera from EV-vaccinated mice contained both IgM and IgG1 reactive reactive to HES and HES supernatant	(Coakley et al., 2017)
Trichuris muris (nematode)	C57BL/6 mice vaccinated twice with EVs no adjuvant subcutaneously	Vaccination deceased worm burden by ~60%. Lysed EVs had similar results to sham control	Vaccination boosted IgG1 and IgG2a/c serum antibody responses to ES depleted of EVs. Range of IgG antibodies in sera against EV components 50–200 kDa in size. Possible targets identified	(Shears et al., 2018)
Echinostoma caproni (trematode)	Balb/c mice vaccinated twice with EVs no adjuvant subcutaneously	No difference in worm burden seen. Vaccination decreased EPG by ~60%. Delay in parasite development. Increase in survival rate of mice	Exosomes elicited significant IgM and IgG response in serum. IgG1, 2b and 3 subtypes responsible for IgG increase. Antibodies against exosome/ESP components mainly 90 kDa in size. Bands the same for immunisation with exosomes and infected animals. Possible targets identified	(Trelis et al., 2016)
Opisthorchis viverrini (trematode)	Hamsters vaccinated 3 times with EVs + alum i.p.	Vaccination decreased worm burden by 27%, EPG reduced by 32%. Average length of worms shorter	Sera showed increase in IgG against EVs both pre and post challenge. Antibodies from vaccinated hamsters blocked uptake of EVs by cholangiocytes	(Chaiyadet et al., 2019)

HES, Heligmosomoides polygyrus excretory/secretory products; EPG, eggs per gram.