TY - JOUR
T1 - Dominant negative suppression of major histocompatibility complex genes occurs in trophoblasts
AU - Coady, Michael A.
AU - Mandapati, Divakar
AU - Arunachalam, Balasubramanian
AU - Jensen, Kari
AU - Maher, Stephen E.
AU - Bothwell, Alfred L.M.
AU - Hammond, Graeme L.
PY - 1999/6/15
Y1 - 1999/6/15
N2 - Background. Polymorphic class I and II major histocompatibility complex (MHC) genes are not transcribed in trophoblasts although many immune system cells express these genes constitutively. To study the molecular biology of MHC suppression for the purposes of potential transgenic animal development, we examined the effect on MHC expression in B cells by fusing them with trophoblasts. Methods. Trophoblasts and B cells with separate selection markers were fused with polyethylene glycol. After growth in double selection media, the hybrids were analyzed for HLA-A, -B, -C, -DR, -DP, and -DQ expression by fluorescence-activated cell scanning and class I and H mRNA by Northern blotting. Class H promoter activity in trophoblasts was then analyzed by transfection of a lethal reporter construct and subsequently, the class II transactivator. Results. Class I and II surface antigens and their corresponding mRNA were completely suppressed in the hybrids. The lethal reporter construct demonstrated that class II suppression resulted from lack of activation of the class II promoter. This in turn was caused by lack of functional class II transactivator. Conclusions. These data indicate that dominant negative trophoblast factors, either directly or indirectly, suppress expression of the MHC genes. If these factors can be cloned, the potential exists for developing transgenic animals that cannot express MHC or peptide antigen to T cell receptors through the MHC system.
AB - Background. Polymorphic class I and II major histocompatibility complex (MHC) genes are not transcribed in trophoblasts although many immune system cells express these genes constitutively. To study the molecular biology of MHC suppression for the purposes of potential transgenic animal development, we examined the effect on MHC expression in B cells by fusing them with trophoblasts. Methods. Trophoblasts and B cells with separate selection markers were fused with polyethylene glycol. After growth in double selection media, the hybrids were analyzed for HLA-A, -B, -C, -DR, -DP, and -DQ expression by fluorescence-activated cell scanning and class I and H mRNA by Northern blotting. Class H promoter activity in trophoblasts was then analyzed by transfection of a lethal reporter construct and subsequently, the class II transactivator. Results. Class I and II surface antigens and their corresponding mRNA were completely suppressed in the hybrids. The lethal reporter construct demonstrated that class II suppression resulted from lack of activation of the class II promoter. This in turn was caused by lack of functional class II transactivator. Conclusions. These data indicate that dominant negative trophoblast factors, either directly or indirectly, suppress expression of the MHC genes. If these factors can be cloned, the potential exists for developing transgenic animals that cannot express MHC or peptide antigen to T cell receptors through the MHC system.
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U2 - 10.1097/00007890-199906150-00012
DO - 10.1097/00007890-199906150-00012
M3 - Article
C2 - 10385086
AN - SCOPUS:0033564786
SN - 0041-1337
VL - 67
SP - 1461
EP - 1467
JO - Transplantation
JF - Transplantation
IS - 11
ER -