Cloning, expression and purification of Eimeria maxima gametocyte antigen-EmGam56 for control of poultry coccidiosis.

Poultry coccidiosis is an important devitalizing enteric protozoan disease caused by a group of obligatory intracellular apicomplexan parasites of the Genus Eimeria contributing to major economic loss in commercial poultry worldwide. As the current method of chemotherapeutic control using ionophores in feed had led to development of drug resistant isolates, the need for development of prophylactic vaccines is the most viable alternate and eco-friendly control strategy as on date. Of the several candidate vaccines, the EmGam 56 is one of the most promising candidates which protect the birds against E. maxima, E. tenella and E. acervulina, the three most pathogenic coccidian species infecting commercial chicken. EmGam56 is a major wall forming component of macrogametocyte of E. maxima and a candidate with high immunogenicity and low virulence. The present study was planned and carried out for the generation of E.coli expressed recombinant gametocyte antigen-EmGam56 using pET 28(a+) as cloning vector and BL21 DE3 (pLysS) as prokaryotic expression system in a Bio-fermentor (New Brunswick™ Scientific BioFlo 310). The recombinant protein was purified by conventional (Ammonium sulphate precipitation) and by automatic purification system (AKTA prime) in Ni-NTA column for a planned immunization trial with experimental chickens.