RESUMEN

Urine and breast milk represent the main routes of human cytomegalovirus (HCMV) transmission but the contribution of renal and mammary epithelial cells to viral excretion remains unclear. We observed that kidney and mammary epithelial cells were permissive to HCMV infection and expressed immediate early, early and late antigens within 72 h of infection. During the first 24 h after infection, high titers of infectious virus were measured associated to the cells and in culture supernatants, independently of de novo synthesis of virus progeny. This phenomenon was not observed in HCMV-infected fibroblasts and suggested the sequestration and the release of HCMV by epithelial cells. This hypothesis was supported by confocal and electron microscopy analyses. The sequestration and progressive release of HCMV by kidney and mammary epithelial cells may play an important role in the excretion of the virus in urine and breast milk and may thereby contribute to HCMV transmission.

Asunto(s)

Infecciones por Citomegalovirus/virología , Citomegalovirus/fisiología , Células Epiteliales/virología , Riñón/virología , Glándulas Mamarias Humanas/virología , Línea Celular , Citomegalovirus/genética , Femenino , Fibroblastos/virología , Humanos , Riñón/citología , Glándulas Mamarias Humanas/citología , Replicación Viral

RESUMEN

The fetus and infant are highly susceptible to viral infections. Several viruses, including human cytomegalovirus (CMV), cause more severe disease in early life compared with later life. It is generally accepted that this is a result of the immaturity of the immune system. gammadelta T cells are unconventional T cells that can react rapidly upon activation and show major histocompatibility complex-unrestricted activity. We show that upon CMV infection in utero, fetal gammadelta T cells expand and become differentiated. The expansion was restricted to Vgamma9-negative gammadelta T cells, irrespective of their Vdelta chain expression. Differentiated gammadelta T cells expressed high levels of IFN-gamma, transcription factors T-bet and eomes, natural killer receptors, and cytotoxic mediators. CMV infection induced a striking enrichment of a public Vgamma8Vdelta1-TCR, containing the germline-encoded complementary-determining-region-3 (CDR3) delta1-CALGELGDDKLIF/CDR3gamma8-CATWDTTGWFKIF. Public Vgamma8Vdelta1-TCR-expressing cell clones produced IFN-gamma upon coincubation with CMV-infected target cells in a TCR/CD3-dependent manner and showed antiviral activity. Differentiated gammadelta T cells and public Vgamma8Vdelta1-TCR were detected as early as after 21 wk of gestation. Our results indicate that functional fetal gammadelta T cell responses can be generated during development in utero and suggest that this T cell subset could participate in antiviral defense in early life.

Asunto(s)

Infecciones por Citomegalovirus/inmunología , Citomegalovirus/inmunología , Feto/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Subgrupos de Linfocitos T/inmunología , Secuencia de Aminoácidos/genética , Antígenos de Superficie/metabolismo , Complejo CD3/genética , Complejo CD3/inmunología , Recuento de Células , Diferenciación Celular/inmunología , Quimiocinas/genética , Regiones Determinantes de Complementariedad/genética , Regiones Determinantes de Complementariedad/inmunología , Citocinas/genética , Citotoxicidad Inmunológica/inmunología , Femenino , Sangre Fetal/citología , Sangre Fetal/inmunología , Feto/virología , Expresión Génica/genética , Expresión Génica/inmunología , Perfilación de la Expresión Génica , Edad Gestacional , Granzimas/genética , Humanos , Inmunofenotipificación , Interferón gamma/genética , Activación de Linfocitos/inmunología , Embarazo , Receptores de Antígenos de Linfocitos T gamma-delta/genética , Receptores de Quimiocina/genética , Receptores de Células Asesinas Naturales , Subgrupos de Linfocitos T/metabolismo