Boer goats appear to lack a functional IgA and eosinophil response against natural nematode infection

Abstract

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.

Kinetics of IgA and eosinophils following a low‐dose, predominantly Haemonchus contortus infection of Boer goats

“…In sheep, parasite‐specific immunoglobulin A (IgA) activity and eosinophilia are negatively associated with faecal egg counts; that is high immune responses are associated with low faecal egg counts. In contrast, natural infections in Scottish Cashmere and Creole goats with predominantly Teladorsagia circumcincta and Haemonchus contortus have not shown these negative associations In addition, there was no negative association between FEC and parasite‐specific IgA activity or eosinophil responses in Boer goats in a mixed natural infection dominated by T circumcincta . In the same study, molecular modelling suggested that the IgA receptor on eosinophils was dysfunctional.…”

“…The original McMaster technique to count nematode eggs in faeces was modified . As each faecal sample had two replicates where four McMaster chambers were used to count the nematode eggs, the number of eggs per gram (epg) of faeces was obtained by multiplying the total number of eggs counted by 25.…”

“…Preparation of faecal culture followed our previously published procedure except that the incubation period at room temperature was seven days. Preparation of L3 for identification and enumeration also followed our previously published procedure .…”

“…Preparation of faecal culture followed our previously published procedure except that the incubation period at room temperature was seven days. Preparation of L3 for identification and enumeration also followed our previously published procedure . The L3 were enumerated and identified by observing their head and sheath tail morphology based on the manual provided by Ministry of Agriculture, Fisheries and Food of Great Britain (1986).…”

“…Packed cell volume (PCV) was measured by filling glass capillary tubes with blood samples from EDTA tubes, sealed with Cristaseal (Hawksley and Sons Ltd), centrifuged at 220 rcf for 5 minutes and read with a rotoreader …”