Bile and serum immunoglobulin levels during primary and secondary infections with Eimeria tenella in chickens.

Using a radial immunodiffusion assay, total bile and serum IgG, IgM and IgA were measured following primary and secondary exposures to Eimeria tenella. Neither IgG nor IgM could be detected consistently in bile. Biliary IgA peaked at Days 6 and 10 following a primary infection of either 5000 or 10,000 oocysts and remained elevated following a subsequent 10,000-oocyst challenge at Day 10. Serum IgG and IgM levels were not influenced by parasitism and measurable concentrations of serum IgA were not detected.