Antigenic Diversity inEimeria maximaand the Influence of Host Genetics and Immunization Schedule on Cross-Protective Immunity

Abstract

Eimeria spp. are a group of highly successful intracellular protozoan parasites that develop within enterocytes. Eimeria maxima from the chicken is characterized by high immunogenicity (a small priming infection gives complete immunity to subsequent homologous challenge) and naturally occurring antigenically variant populations that do not completely cross-protect. In this study we examined the expression of antigenic diversity in E. maxima, as manifested by cross-strain protection in a series of inbred chicken lines. The IAH line of Light Sussex chickens and all lines of inbred White Leghorns were susceptible to primary infections with either of two strains (H and W) of E. maxima and were protected completely against challenge with the homologous strain of parasite. The extent of cross-protection against the heterologous parasite strain varied from 0 to almost 100% depending on host genetics. Interestingly, in one inbred line of chickens (line 15I) the cross-protective phenotype was directional and intensely influenced by the infection history of the host. The basis for the observed variation in cross-protection is not known, but our results suggest that the major histocompatibility complex is not a major genetic component of the phenotype. These results are discussed in relation to the number of protective antigens presented by complex pathogens and the development of immunoprotective responses in hosts of different genetic backgrounds.

Carotenoid trade-off between parasitic resistance and sexual display: an experimental study in the blackbird ( Turdus merula )

“…Coccidian infestations are known to produce a large amount of free radicals (Allen 1997a,b) and are highly immunogenic (Martin et al 1997;Yun et al 2000;Smith et al 2002;Horak et al 2004). Infected birds were therefore forced to fight off the infection.…”

Prevalence and Cross-Immunity of Eimeria Species on Korean Chicken Farms

“…Eimeria infections inflict severe economic loss due to extensive destruction of the enteric epithelium, resulting in reduction of feed conversion, body weight gain and egg production, and increased morbidity and mortality [12,15,17]. Seven species of Eimeria that infect chickens invade the intestinal epithelium in a region-specific manner, and induce both species-specific immunity and, in some cases of E. maxima, strain-specific immunity [17,20,21]. Namely, different populations of E. maxima including field isolates exhibit substantial immunological diversity [1,13,21].…”

“…Seven species of Eimeria that infect chickens invade the intestinal epithelium in a region-specific manner, and induce both species-specific immunity and, in some cases of E. maxima, strain-specific immunity [17,20,21]. Namely, different populations of E. maxima including field isolates exhibit substantial immunological diversity [1,13,21]. Chickens may be simultaneously infected with multiple species of Eimeria in intensively reared poultry farms [16,18].…”

An assessment of opportunities to dissect host genetic variation in resistance to infectious diseases in livestock

“…Genetic differences in resistance observed in inbred lines have been reported for all seven species (Bumstead and Millard, 1992). Differences were also reported between IAH light Sussex chickens and the same inbred lines (Smith et al, 2002). Large differences have also been reported in outbred populations both for resistance to infection and for the impact of infection on production traits (Pinard-van der Laan et al, 1998).…”