Progress in the development of subunit vaccines for gastrointestinal nematodes of ruminants

Abstract

SummaryThe global increase in anthelmintic resistant nematodes of ruminants, together with consumer concerns about chemicals in food, necessitates the development of alternative methods of control for these pathogens. Subunit recombinant vaccines are ideally placed to fill this gap. Indeed, they are probably the only valid option for the long-term control of ruminant parasitic nematodes given the increasing ubiquity of multidrug resistance in a range of worm species across the world. The development of a subunit multicellular parasite vaccine to the point of practical application would be a groundbreaking step in the control of these important endemic infections of livestock. This review summarizes the current status of subunit vaccine development for a number of important gastrointestinal nematodes of cattle and sheep, with a focus on the limitations and problems encountered thus far, and suggestions as to how these hurdles might be overcome. K E Y W O R D Sgastrointestinal nematodes, ruminants, vaccines

Mind the gaps in research on the control of gastrointestinal nematodes of farmed ruminants and pigs

“…Several recombinant vaccine antigens, expressed in Escherichia coli , insect cells, Pichia pastoris or the free‐living nematode Caenorhabditis elegans , failed to confer protection in vaccine trials (Cachat, Newlands, Ekoja, McAllister, & Smith, ; Geldhof, Meyvis, Vercruysse, & Claerebout, ; Roberts et al., ; Vlaminck et al., ). Current research is focusing on differences in protein folding or secondary modifications, such as glycosylation, between the native and recombinant proteins as possible reasons for the lack of protection (Matthews et al., ). Recently, a number of recombinant vaccines showed promising results.…”

“…For example, it has been suggested that a reduction of cumulative FEC by around 60% during the first 2 months after turnout would sufficiently reduce pasture infection levels to protect young stock against O. ostertagi and C. oncophora until the end of the grazing season (Claerebout, Knox, & Vercruysse, ). However, this hypothesis is based on the assumption that a typical first grazing season in Western Europe lasts for about 6 months, and vaccine efficacy requirements are likely to be different in regions with continuous grazing throughout the year, such as parts of South America and New Zealand (Matthews et al., ). Vaccine efficacy requirements may also be different in calves or lambs that co‐graze with their dams.…”

Controlling nematode infections in sheep: application of HACCP

“…However, it is unlikely that these vaccines will achieve a greater than 90 per cent reduction in egg counts and, as a consequence, whole-flock strategies are still necessary (Matthews and others 2016). …”

Helminth Vaccines in Ruminants

“…1 Vaccines are considered a favorable option, because of the durable protection they can provide and a lack of chemical residues in animal products and the environment. 2 The principle of vaccination is to induce immunologic protection in a host against a subsequent infection. For this, the immune system can be stimulated with either the weakened or killed pathogen or proteins/antigens from it, the so-called subunit vaccines ( Fig.…”