DETECTION OF HOST DNA-SEQUENCES INCLUDING THE H-2 LOCUS OF THE MAJOR HISTOCOMPATIBILITY COMPLEX IN SCHISTOSOMES

The mouse type 2 Alu (B2) sequence was detected in both DNAs of Schist osoma mansoni and S. japonicum except for the cercarial stage by the p olymerase chain reaction (PCR). Using several kinds of mouse STMS (seq uence tagged microsatellite site) primer sets, PCR products related to the host were found in the DNAs of S. mansoni as well as of S. japoni cum. Products could be detected only in the DNA of S. japonicum using certain STMS primer sets. The fact that no products could be amplified from the DNAs of both parasites when other kinds of STMS primer sets were used suggests unequal incorporation of the host DNA into the schi stosomes. Furthermore, the sequence of the N-terminal domain of H-2, t he mouse major histocompatibility complex (MHC), was detected in the D NAs from S. mansoni miracidium, male adult and S. japonicum adults, wh ereas the sequence of the C-2 domain of H-2 was found only in the DNAs of S. japonicum adults. This evidence that host DNA sequences, includ ing the class I MHC, exist heterogeneously in the DNAs of schistosomes might provide an important insight for further understanding of host- parasite immune interactions.