Gastrointestinal nematodes (GIN) pose an existential threat to small ruminants such as sheep and goats (Hoste et al., 2010). The two species have evolved different strategies to minimise the threat (Hoste et al., 2008). In sheep, the immune response is the major mechanism of defence (McRae et al., 2015). The nematode Teladorsagia circumcincta is the dominant nematode in cool temperate areas of the world and possibly there is more known about the mechanisms of protective immunity to this nematode than any other (Stear et al., 1995). There are three major signs of immunity (Smith et al., 1984). The first is reduced establishment and survival which is strongly associated with a local type 1 hypersensitivity response (Miller, 1984; Murphy et al., 2010; Stear et al., 1995). The second sign of resistance is an increased number of inhibited larvae which has been weakly associated with a local IgA response (Smith et al., 1985; Strain et al., 2002) although there is some doubt as to whether the IgA response is quick enough to influence larval inhibition (Halliday et al., 2010). Further, larval inhibition can also be influenced by density-dependent Research paper Boer goats appear to lack a functional IgA and eosinophil response against natural nematode infection Basripuzi (Basripuzi is the surname of the first author.

Nematode infection is one of the most severe diseases faced by small ruminants such as sheep and goats. 1 The two species have developed different ways to reduce the ravages of disease. Sheep mount strong immune responses while goats minimize exposure by browsing leaves rather than grazing grass. 2 In both sheep 3,4 and goats, 5-7 some breeds mount more effective immune responses than others.Three methods that are being explored to control nematode infections in small ruminants are the use of genetically resistant animals, 8-11 dietary protein supplementation 12-16 and the development of vaccines. 17,18 These three methods depend at least partly upon enhancing the immune response to nematodes. 19 Therefore, characterizing the immune response in goats and identifying the reasons why many goats mount relatively weak responses compared with sheep could provide useful insights for nematode control. Abstract Aims: Most breeds of goat are more susceptible to nematode infection than sheep, and this appears to be a consequence of less effective immune responses. Several papers have considered the effectiveness of eosinophils and immunoglobulin A (IgA) in goats but differences in the induction of responses have not been studied in the same detail. The aim of this study was to look at the induction of eosinophil and IgA responses in Boer goats reared indoors under intensive conditions. Methods and results: The goats were experimentally infected with a low dose of 2400 Haemonchus contortus, Trichostrongylus spp. and Oesophagostomum spp. at a 6:1:1 ratio. Faecal egg counts (FEC), packed cell volume (PCV), IgA activity against third-stage larvae and peripheral eosinophilia were measured twice a week for eight weeks. The infection generated an IgA response but did not significantly increase peripheral eosinophilia in the 25 infected kids compared with the 4 control animals.FEC was not associated with IgA activity or eosinophilia. Conclusion:A detailed analysis of IgA and eosinophil responses to deliberate nematode infection in Boer goats showed that there was an increase in nematode-specific IgA activity but no detectable eosinophil response. In addition, there was no association between increased IgA activity or eosinophilia with egg counts and worm burdens. These suggest that IgA and eosinophils do not act to control nematode infection in goats.

Eosinophils are important immune cells that have been implicated in resistance to gastrointestinal nematode (GIN) infections in both naturally and experimentally infected sheep. Proteins of particular importance appear to be IgA-Fc alpha receptor (FcαRI), C-C chemokine receptor type 3 (CCR3), proteoglycan 3 (PRG3, major basic protein 2) and EPX (eosinophil peroxidase). We used known human nucleotide sequences to search the ruminant genomes, followed by translation to protein and sequence alignments to visualize differences between sequences and species. Where a sequence was retrieved for cow, but not for sheep and goat, this was used additionally as a reference sequence. In this review, we show that eosinophil function varies among host species. Consequently, investigations into the mechanisms of ruminant immune responses to GIN should be conducted using the natural host. Specifically, we address differences in protein sequence and structure for eosinophil proteins.

Teladorsagia circumcincta is the most important gastrointestinal parasite in the livestock industry in temperate regions around the world, causing great economic losses. The infective third-stage larvae (L3) of Teladorsagia circumcincta secrete a large number of excretory-secretory (E/S) molecules, some of which are likely to play critical roles in modulating the host immune response. One of the most abundant E/S molecules is a protein termed Tci-gal-1, which has similarity to mammalian galectins. Galectins are a family of carbohydrate-binding molecules, with characteristic domain organisation and affinity for β-galactosids that mediate a variety of important cellular functions including inflammation and immune responses. To understand the role of Tci-gal-1 at the host–parasite interface, we used a proteomics pull-down approach to identify Tc-gal-1 interacting proteins from sheep abomasal scrapes and whole tissue. A total of 135 unique proteins were identified from whole abomasal tissue samples, while 89 proteins were isolated from abomasal scrape samples. Of these proteins, 63 were present in both samples. Many of the host proteins identified, such as trefoil factors and mucin-like proteins, play critical roles in the host response. The identification of Tci-gal-1 binding partners provides new insights on host–parasite interactions and could lead to the development of new control strategies.