Babesia bigemina: Sporozoite Isolation from Boophilus microplus Nymphs and Initial Immunomolecular Characterization
It has been hypothesized that babesial sporozoites express specific antigens that induce protective immunologic responses in cattle. However, they remain uncharacterized, partly for lack of research on the sporozoite stage of Babesia spp. This field suffers from complete knowledge of parasite development in the tick salivary gland; limited amounts of sporozoites from ticks, and a lack of protocols for induction and purification of sporozoites. In this work, Boophilus microplus larvae infected with B. bigemina were fed on susceptible cattle. Nymphs were collected and macerates were separated by a Percoll density gradient. Microscopic analysis of Giemsa-stained smears showed a larger number of sporozoites from nymphs fed for 9 days. Percoll-purified sporozoites were observed in large numbers in groups or individually and free of tick cells. RT-PCR analysis of total RNA extracted from purified sporozoites indicated transcription of the rhoptry associate protein 1 (rap-1) genes
babesia bigemina sporozoite boophilus microplus nymph rhoptry-associated protein 1 heat shock protein 20