Conservation of proteins involved in oocyst wall formation in Eimeria maxima, Eimeria tenella and Eimeria acervulina

Abstract

Vaccination with proteins from gametocytes of Eimeria maxima protects chickens, via transfer of maternal antibodies, against infection with several species of Eimeria. Antibodies to E. maxima gametocyte proteins recognise proteins in the wall forming bodies of macrogametocytes and oocyst walls of E. maxima, Eimeria tenella and Eimeria acervulina. Homologous genes for two major gametocyte proteins – GAM56 and GAM82 – were found in E. maxima, E. tenella and E. acervulina. Alignment of the predicted protein sequences of these genes reveals that, as well as sharing regions of tyrosine richness, strong homology exists in their amino-terminal regions, where protective antibodies bind. This study confirms the conservation of the roles of GAM56 and GAM82 in oocyst wall formation and shows that antibodies to gametocyte antigens of E. maxima cross-react with homologous proteins in other species, helping to explain cross-species maternal immunity.

Apicomplexan Parasite, Eimeria falciformis, Co-opts Host Tryptophan Catabolism for Life Cycle Progression in Mouse

“…1D). The homologs of EfGam56 and EfGam82 proteins are expressed in a macrogamont-specific manner in the avian species of Eimeria (23). Taken together, we show the entire natural development of E. falciformis in mouse, which consists of distinct asexual and sexual stages in the epithelial cells of host caecum.…”

The comparative analysis of infection pattern and oocyst output in Eimeria tenella, E. maxima and E. acervulina in young broiler chicken

“…The development of sexual stages (micro-and macro-gametocytes) and formation of oocysts were observed within epithelial cells of the small intestine (duodenum jejunum) after infection with (144 h post infection (PI) and (96 h PI) and of the caecum after infection with (136 h PI) [5].This intracellular parasite has a complex lifecycle, where it passes through asexual and sexual stages of development. The final stage of development, the oocyst, is excreted from the host and, under the appropriate conditions of temperature and humidity, undergoes a process known as sporulation, where it becomes infective.…”

Stage-specific expression of protease genes in the apicomplexan parasite, Eimeria tenella

“…Gametocytes from E. tenella- infected caeca were lysed and immediately incubated with or without protease inhibitors for various lengths of time, and the native GAM56 protein analysed by SDS-PAGE and western blotting with anti-GAM56 antibodies, as described previously [20,21], to track the disappearance of the protein to determine whether any inhibitors could prevent the degradation observed in the presence of native gametocyte proteases. The precise epitopes recognised by the anti-GAM56 polyclonal antibodies are not known for E. tenella though there is some evidence, from work with E. maxima [21], that they are located in the conserved amino-terminus of the protein.…”

“…The precise epitopes recognised by the anti-GAM56 polyclonal antibodies are not known for E. tenella though there is some evidence, from work with E. maxima [21], that they are located in the conserved amino-terminus of the protein. The anti-GAM56 antibodies are, thus, very useful for sensitive and specific tracking of the degradation of GAM56.…”