Screening of Theileria parva apicomplexan antigen homologs for induction of MHC CD4+ and CD8+ T-cell responses

Theileria parva, an intracellular apicomplexan pathogen transmitted by Rhipicephalus appendiculatus ticks, infects and transforms lymphocytes of cattle and African buffalo causing the disease called East Coast fever (ECF). The genome of of T. parva was sequenced in order to facilitate research on parasite biology, assist the identification of schizont antigens for vaccine development and extend comparative apicomplexan genomics. In the present study, eight putative apicomplexan antigens were identified from literature and their homologs purified from a T. parva Muguga schizont cDNA library. These were immunoscreened for MHC CD4(+) and CD8(+) CTL response. The results showed that of the expressed proteins, only the T. parva T-complex 1 protein zeta subunit ortholog was found to elicit CD4(+) response; none elicited CD8(+) response. The elicitation of CD4(+) T cell response by the T. parva T complex Protein-1 zeta subunit homolog indicates that it is a candidate T-helper cell target antigen.