Analysis Of Antigenic Characteristics Of Taenia Pisiformis And Protective Efficacy Of TPO18Recombinant Protein

Rabbits and murine were infected orally with the eggs in gravid proglottid, which was secreted from dogsthat experimentally infected with different numbers of Taenia pisiformis. Circulating antibody levels in rabbitsand murine infected with Cysticercus pisiformis experimentally were monitored weekly by ELISA. The resultsin the rabbits group indicated that the antibody levels were increased from the valley on the8th day to the peakon the43th day post-infection and maintained the high level to the end of the experiment（on the63th daypost-infection）. The antibody levels in the murine group started to increase on the8th day post-infection andwere up to the highest level on the38th day post-infection, which remained11days（on the49th day postinfection）.The results demonstrated that a positive relationship existed between the number of cysts and thetiters of circulating antibodies, antibody level of the largest infectious dose group rise fastest, and it was higherthan the other infection groups.The proteins from different developmetal stages of Taenia pisiformis, Cysticercus cellulosae fluid,Coenurus cerebralis and Coenurus cerebralis fluid were separated by SDS-PAGE.4to8protein strips,ranging from30.4to114.9ku, were separated from these strains. Thereinto, thirteen antigens with molecularweight of59.4ku could be recognized by the50th day positive serum against Cysticercus pisiformis inWestern-blot. Cross reactions were found between Coenarus cerebralis and Cysticercus pisiformis.A pair of primers was designed based on the conserved region of other Taeniidae18ku gene. The TPO18gene was amplified by RT-PCR from RNA of oncosphere of Taenia pisiformis. Sequencing analysis revealedthat the length of the ORF was339bp, which can encode112amino acids. The recombinant pGEX-TPO18was then transformed into E.coli BL21. The products of expression were analyzed by SDS-PAGE afterimproving the expression conditions. Rabbits were immunized with the purified recombinant pGEX-TPO18protein add Freund’s adjuvant,206adjuvant, Al(OH)3adjuvant respectively. Each rabbit was injected with50μg recombinant protein for3times. The immune serum could recognize a38ku band in soluble protein ofTaenia pisiformis. At the34th day after the last immunization, each rabbit infected with1500eggs of T.pisiformis orally.58days after infection, the rabbits were sacrificed and number of cysts in enterocoelia wascounted. ELISA showed that after third immunization, the levels of antibody in sera of immune group weresignificantly higher than those of the control groups. The levels of antibody still maintain a stable level.Compared with control groups, the reduction rate of cysts in immunized sheep was79.13%,65.66%,50.43%respectively. The results showed that Freund’s adjuvant and206adjuvant can produce better immuneprotection than Al(OH)3adjuvant. All the above results supported the development of highly efficientrecombinant vaccines against cysticercosis.