Heterogeneity of class I and class II MHC sequences in Schistosoma mansoni

Abstract

We investigated the genetic variations in class I and class II major histocompatibility complex (MHC) genes of Schistosoma mansoni and the effects of host MHC genotypes. S. mansoni was maintained in combinations of two mouse strains with different MHC genotypes, and the MHC gene sequences of the cercariae were investigated. The detected class I MHC gene sequences were variable, with high similarity between the H-2D(b) murine host and the parasite. For other combinations, however, the parasite sequence was homologous to those of anthropoids. All class II MHC sequences detected in S. mansoni were homologous to those of anthropoids. Our results suggest that the genetic variation in the MHC sequences of S. mansoni is derived in part from the current host, indicating horizontal transfer of the sequences from mammal to parasite.

Heterogeneity of class I and class II MHC sequences in Schistosoma japonicum from different endemic regions in mainland China

“…This could be due to different acceptability of different parasites, or this could be an implication that the sequences were potentially transferable as described for S. mansoni (Okada et al 2006).…”

“…MHC genes have been found on the surfaces of S. japonicum adults (Iwamura et al 1995;Imase et al 2003Imase et al , 2004 and cercariae (Imase et al 2003(Imase et al , 2004, and individual variations have been reported for the class I MHC gene sequences in schistosomes maintained in different hosts, and some MHC I sequences were found to be similar between the host mouse and the schistosome maintained in the host (Imase et al 2001(Imase et al , 2003(Imase et al , 2004. A previous study (Okada et al 2006) showed that S. mansoni could not be able to acquire MHC I genes from BALB/c mice as they did from C57BL/6 mice because of poor ability to acquire the H-2D d sequences. All the MHC II sequences in S. mansoni were quite similar among different S. mansoni adults maintained in different host (mouse) lineages, but the sequences were highly homologous to the anthropoid HLA-DQB2 genes of chimpanzee, gorilla, and human.…”

“…MHC genes are very important in the host immunity and can produce considerable glycoproteins to discriminate endogenous and exogenous tissues (Okada et al 2006). MHC genes have been found on the surfaces of S. japonicum adults (Iwamura et al 1995;Imase et al 2003Imase et al , 2004 and cercariae (Imase et al 2003(Imase et al , 2004, and individual variations have been reported for the class I MHC gene sequences in schistosomes maintained in different hosts, and some MHC I sequences were found to be similar between the host mouse and the schistosome maintained in the host (Imase et al 2001(Imase et al , 2003(Imase et al , 2004.…”

“…Previous studies have shown that the existence of common or host antigens between schistosomes and hosts may contribute to the parasites' ability to evade host immune responses (Imase et al 2003;Okada et al 2006). S. japonicum could obtain the mouse DNA including the class I major histocompatibility complex (MHC) molecule, and the sequence of mouse class I MHC has been found to be incorporated into schistosome adults and inherited throughout their life cycle (Iwamura et al 1995;Imase et al 2004).…”

“…These findings indicate that horizontal and vertical transmission of host DNA sequences occur in schistosomes. Okada et al (2006) found that class I and class II MHC sequences not only could transfer from mammals to S. mansoni, but also exist heterogeneity, and variation in the MHC sequences of S. mansoni is derived in part from the current host.…”