Globule leukocytes in the lumen of the small intestine and the resistance status of sheep infected with parasitic nematodes.

The presence of globule leukocytes in the lumen (LuGLs) of the small intestine was studied in Romney sheep reared parasite free and then experimentally infected or immunized with Trichostrongylus colubriformis infective larvae, or naturally infected when gazed on pasture. It was discovered that high numbers of LuGLs were associated with both parasitic infection and the sheep protective immune response. A high positive correlation was observed between LuGLs and tissue globule leukocytes. The highest correlation (r = 0.92) observed was between larval migration inhibition (LMI) and numbers of LuGLs. This was the only correlation between LMI and other parameters studied. Significant positive correlations were also observed between LuGLs and IgG1 and eosinophils. There was a negative correlation between LuGLs and the number of parasites in the intestine and parasite egg production. Progeny of genetically resistant and susceptible sires had significantly different abilities to produce LuGLs.