Immunoscreening of Schistosoma japonicum adult worm cDNA library with sera of infected rats

Aim To explore the molecular mechanism of natural resistance in rat to infection with Schistosoma japoniucm(Sj),and to provide several useful candidate antigens for developing anti schistosomiasis vaccine Methods Sj adult cDNA library was screened with sera of infected rat,and the inserts of positive clones were specifically amplified by PCR and sequenced Results Seven positive clones were obtained from 3×10 5 phage clones after three rounds of screening The size of these inserts ranged from 0 9kb to 2 0kb Five partial sequences were obtained after preliminary sequencing,one had significant homology with Sj mitochondrial gene,while the others were identified as partial sequences of novel genes Among them,Sj-Cs2(GenBank accession number:AY036580) encodes a transmembrane protein with 206 amino acid,which predicted contains three protein kinase C phosphorylation sites and six N myristoylation sites Conclusion The positive clones may be the genes that relate to natural resistance of rat to schistosome infection The full sequences of the novel genes and their molecular and immunological characteristics are valuable to do further investigation