Immunoprotection of chickens against Eimeria acervulina by recombinant alpha-tubulin protein.

Tubulins are heterodimeric molecules responsible for the polymerization of microtubules in apicomplexan parasites. The alpha-tubulin, a subcellular structural protein of Eimeria acervulina, was cloned and expressed in Escherichia coli as an alpha-tubulin-GST fusion protein. Immunogenicity of the recombinant protein was studied in chickens by subcutaneous injection of 50, 100, or 150 microg of the protein with or without Freund's adjuvant. Immunization with 150 microg alpha-tubulin-GST protein in combination with Freund's adjuvant conferred partial protection against E. acervulina oocyst challenge, as shown by a 36% reduction in oocyst shedding, a marked decrease in intestinal lesion score and a significant increase in body weight gain in comparison with the nonimmunized controls. The results suggest that alpha-tubulin protein may be used as an effective vaccine antigen for the control of Eimeria infection.