Study on screening simulated epitopes of protective antigens of Schistosoma japonicum and their immuno-protective effect / 中国血吸虫病防治杂志

ABSTRACT

Objective To study the immuno-protective effect against Schistosoma japonicum challenge of the positive monoclonal phages which were screened from the 12 mers-phage random peptide library by the new model rabbit serum. Methods The new model was established by injecting the Schistosoma japonicum infection rabbits with inhibitor of phenol oxidose. Positive clones immunoscreened with the new model rabbit sera were absorbed by SEA immune rabbit sera, and 14 clones selected randomly from them were compared and their antigenic ability was identified by ELISA. The two best positive monoclonal phages (No.8, No.13) recognized by the new model rabbit sera were selected to immunize Kunming mice by subcutaneously injecting 1?10~15 pfu positive phages at 0, 2nd, 4th week respectively. After 4 weeks of the last immunity,each mouse was challenged with 40?1 S.japonicum cercariae. All mice were sacrificed after 42 days and the reduction rates of adult worms and the liver eggs were investigated. Results The positive phage clones after immune absorption were weakly recognized by the SEA immune rabbit sera. The 14 monoclonal phages were recognized by the rabbit sera of the new model and the normal model. Especially No.8, No.13 were strongly recognized by the rabbit sera of the new model,while weakly recognized by the SEA immune rabbit sera. The reduction rates of adult worms and liver eggs induced by the monoclonal phage No.13, the monoclonal phage No.8 and the original peptide library were 35.81% and 63.32%, 32.09% and 52.02%, 14.90% and 30.64%, respectively. Conclusion Most clones of simulated epitopes of SEA can be removed by absorbing positive clones with SEA immune rabbit serum .The 14 monoclonal phages from the new model contain the simulated S.japonicum epitope. The two monoclonal phages have higher reduction rates of adult worms and eggs than original 12 mers-phage random peptide library and the positive polyclonal phages.[