[Screening of Schistosoma japonicum adult worm genomic DNA library by specific antibody]

Abstract

S. japonicum adult worm genomic DNA libraries were screened by enzymeimmunoassay. The antigens produced by recombinant lambda gt 11 plaques were transferred to nitrocellulose filters. Clones encoding given antigens were detected with infected rabbit sera (IRS) which were preabsorbed with lysate of induced lambda gt 11 in Y1090 cells. Eight putative positives were picked up from 97 plates in the primary screening and were rescreened a second time, and, 2 of them consistently gave good positive signals in subsequent screenings. One of the phage clones was purified to homogeneity and mixed with Y1089 cells. The expressed products still showed positive when rescreened by ELISA, indicating that the clone encoding S. japonicum antigen could be recognized by IRS. The immunoscreening method described here was able to efficiently isolate single clones encoding S. japonicum antigens. The method has the advantages of screening libraries efficiently, reliably and specifically, and it might open the way to screen genes encoding S. japonicum antigens inducing protective immunity (Fig. 1).