RESUMEN
Human placental trophoblast is critically involved in mediating maternal tolerance of the fetal semiallograft. Genes encoding highly polymorphic major histocompatibility complex (MHC) class I and class II antigens that could provoke maternal immune rejection responses are silenced in trophoblast. However, several MHC class I or class I-related products exhibiting reduced or negligible polymorphism are expressed and assumed to be functionally involved in maintaining pregnancy. The CD1 gene family encodes non-polymorphic MHC class I-like products that have the unusual ability to present non-peptide antigens to T cells. One member, CD1D, is expressed in certain epithelial cells and interacts with a specific T-cell subset that may promote the development of Th2-mediated responses believed to be associated with pregnancy. In this study we examined the expression of CD1D in human trophoblast cell lines and placentally derived trophoblast cells by reverse transcriptase-polymerase chain reaction using CD1D-specific oligonucleotide primers. We have found that CD1D mRNA transcripts are expressed in trophoblast cells and cell lines. We have also identified a novel alternatively spliced CD1D mRNA transcript lacking exon 4. Exon 4-intact and exon 4-deficient CD1D transcripts appear to be differentially expressed in different trophoblast and non-trophoblast cell populations. Our studies suggest that at least one member of the CD1 family is transcribed in human trophoblast.
Asunto(s)
Antígenos CD1/genética , Coriocarcinoma/genética , Proteínas de Neoplasias/genética , Trofoblastos/metabolismo , Neoplasias Uterinas/genética , Antígenos CD1/metabolismo , Secuencia de Bases , Coriocarcinoma/metabolismo , Femenino , Humanos , Datos de Secuencia Molecular , Proteínas de Neoplasias/metabolismo , Embarazo , ARN Mensajero/genética , ARN Neoplásico/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transcripción Genética , Células Tumorales Cultivadas , Neoplasias Uterinas/metabolismoRESUMEN
The expression of HLA class I Ag by term human amnion epithelial cells was investigated. In immunostaining and FACS analysis, mAb to monomorphic class I Ag reacted extensively with amnion cells, whereas polymorphic mAb reactivity was more limited and variable. Further studies were conducted on amnion cell preparations containing negligible contaminants. Northern analysis with use of locus-specific probes demonstrated that amnion expresses two class Ib genes, HLA-E and HLA-G. Radio-immunoprecipitation with use of monomorphic mAb identified two fully glycosylated cell surface class I H chains of 44 and 41 kDa; polymorphic mAbs failed to immunoprecipitate the 41-kDa product, although 44-kDa products, typical of class Ia Ag, were identified in some preparations. Class I H chains were isolated from amnion by affinity chromatography. Microsequencing revealed that the first nine residues of the N-terminus of the 41-kDa product aligned perfectly only with HLA-E. Overall, amnion at term appears to express class Ib Ag with limited class Ia Ag. HLA-G is therefore expressed in two extrafetal epithelia: amnion and trophoblast. Identification of the class Ib protein HLA-E in amnion epithelium may have implications for preterm labor that can be associated with infection of the placental membranes.
Asunto(s)
Amnios/inmunología , Antígenos HLA/biosíntesis , Antígenos HLA/genética , Antígenos de Histocompatibilidad Clase I/biosíntesis , Antígenos de Histocompatibilidad Clase I/genética , Amnios/citología , Anticuerpos Monoclonales/inmunología , Secuencia de Bases , Northern Blotting , Células Cultivadas , Cromatografía de Afinidad , Femenino , Citometría de Flujo , Regulación de la Expresión Génica/inmunología , Glicósido Hidrolasas/fisiología , Antígenos HLA/inmunología , Antígenos HLA-G , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Immunoblotting , Datos de Secuencia Molecular , Pruebas de Precipitina , Trofoblastos/citología , Antígenos HLA-ERESUMEN
The (-)-enantiomer of 2'-deoxy-3'-thiacytidine (3TC) was found to be a potent and selective inhibitor of human immunodeficiency virus types 1 (HIV-1) and 2 (HIV-2) in vitro. We determined its antiviral activity against a number of laboratory strains of HIV-1 and HIV-2 in a range of CD4-bearing lymphocyte cell lines (mean 50% inhibitory concentration [IC50] range, 4 nM to 0.67 microM). 3TC was also active against a range of HIV-1 strains in peripheral blood lymphocytes (mean IC50 range, 2.5 to 90 nM). The IC50 for cytotoxicity in seven lymphocyte cell cultures, including human peripheral blood lymphocytes, ranged from 0.5 to 6 mM. 3TC had no detectable antiviral activity against a range of other viruses or in cells chronically infected with HIV-1 or HIV-2. The effects of time of addition of the compound and varying the multiplicity of infection on the antiviral activity of 3TC were determined. The results showed that 3TC is a potent and selective inhibitor of HIV-1 and HIV-2 replication in vitro.
Asunto(s)
VIH-1/efectos de los fármacos , VIH-2/efectos de los fármacos , Zalcitabina/análogos & derivados , Muerte Celular/efectos de los fármacos , Células Cultivadas , Didanosina/farmacología , Células Gigantes/efectos de los fármacos , Transcriptasa Inversa del VIH , Humanos , Lamivudine , ADN Polimerasa Dirigida por ARN/análisis , Tritio , Replicación Viral/efectos de los fármacos , Zalcitabina/farmacología , Zidovudina/farmacologíaRESUMEN
Racemic 2'-deoxy-3'-thiacytidine (BCH 189) is a dideoxycytidine analog having a sulfur atom in place of the 3' carbon. The enantiomers of BCH 189 have been resolved and found to be equipotent in antiviral activity against human immunodeficiency virus types 1 and 2. However, the (-)-enantiomer (3TC) is considerably less cytotoxic than the (+)-enantiomer.