Evidence for expression of both classical and non-classical major histocompatibility complex class I genes in bovine trophoblast cells.
OBJECTIVE
During the third trimester of pregnancy bovine trophoblast cells in the interplacentomal and arcade regions of the placenta express major histocompatibility complex class I (MHC-I) antigens. At parturition immunological recognition of MHC-I antigens appears to contribute to normal placental release. Therefore, we hypothesized that during late pregnancy bovine trophoblast cells express polymorphic, classical MHC-I antigens.


METHODS
Cloning, microarray screening and sequencing of cDNA were used to study transcription of MHC-I genes in peripheral blood mononuclear cells (PBMC) and interplacentomal, trophoblast cells. Real-time reverse transcription, polymerase chain reaction (RT-PCR) was used to compare the abundance of MHC-I transcripts in PBMC and trophoblast cells.


RESULTS
Screening of cloned MHC-I cDNA on MHC-I microarrays indicated that in PBMC 90-98% of MHC-I transcripts were encoded by classical MHC-I genes with the remainder encoded by non-classical MHC-I genes. In contrast, 21-66% of MHC-I transcripts from interplacentomal trophoblast cells were from classical genes and 34-79% were from non-classical genes. Transcripts from four non-classical MHC-I loci were identified by sequence analysis. Real-time RT-PCR indicated that the overall levels of MHC-I gene expression in PBMC and trophoblast were similar.


CONCLUSIONS
Bovine interplacentomal trophoblast cells express both classical and non-classical MHC-I genes, but the relative level of expression varies considerably.
Davies
Christopher J
CJ
Department of Veterinary Microbiology and Pathology & Center for Reproductive Biology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USA. cdavies@vetmed.wsu.edu
Eldridge
Jennifer A
JA
Fisher
Patricia J
PJ
Schlafer
Donald H
DH
D000818:Animals; D002417:Cattle; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010802:Phylogeny; D010920:Placenta / Q000276:immunology; D012313:RNA / Q000235:genetics / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014158:Transcription, Genetic / Q000235:genetics / Q000276:immunology; D014327:Trophoblasts / Q000276:immunology*
D018076:DNA, Complementary; D015395:Histocompatibility Antigens Class I; D012313:RNA