[Expression and role of complement regulatory proteins on XXXX gametes and pre-implantation embryos].

@entity1 @entity3432 @entity1009 @entity805 @entity806 @entity9819
@entity1 gametes and pre-implantation embryos express selectively several complement regulatory proteins. @entity806 ( @entity806 , @entity806 ) and @entity9819 ( @entity9819 , @entity9819 ) are regulators for C3 convertases and protectin ( @entity1009 ) is an inhibitor of the membrane attack complex. These three proteins were identified on @entity1 sperm and found to be functional. @entity9819 and @entity1009 were both expressed by the plasmic membrane of unfertilized oocytes and pre-implantation embryos. @entity806 was not present on unfertilized oocytes but appeared at the 6/8 cell-stage embryo when @entity1 gene expression first occurs. @entity3432 ( @entity3432 , @entity3432 ) and MHC class I antigens were not found on oocytes neither on embryos. Such a selective expression of complement regulatory proteins associated with the lack of MHC class I antigens may represent an immune protective mechanism by which @entity1 gametes and pre-implantation embryos escape from complement-mediated damage during their travel through the female genital tract. Indeed uterine, tubal and follicular fluids contain all the components of the complement cascade, including classical and alternative pathways. Nevertheless participation of @entity806 and @entity1009 in cell to cell interaction during fertilization and/or implantation cannot be excluded. @entity1009 is an adhesive molecule involved in the rosette phenomena and @entity806 has been described as the @entity1 receptor for @entity805 , which binds through a fusion protein. Monoclonal antibodies raised against these two proteins ( @entity806 and @entity1009 ) are able to inhibit heterospecific fertilization between zona-free hamster oocytes and @entity1 spermatozoa suggesting the role of these proteins during fertilization.
