Role of lymphotoxin and homeostatic chemokines in the development and function of local lymphoid tissues in the respiratory tract

Los órganos linfoides secundarios tienen una posición anatómica estratégica, con la finalidad de reclutar células presentadoras de antígeno activadas, células "naïve" y poblaciones de células T y B que se encuentran recirculando en la periferia. La estructura de los órganos linfoides secundarios, la cual incluye zonas definidas de células T y B, poblaciones especiales de células estromales, vénulas del endotelio alto y vasos linfáticos, ha evolucionado para facilitar los encuentros entre células presentadoras de antígeno y linfocitos, facilitando la proliferación y diferenciación de células B y T estimuladas por antígenos. La mayoría de los mecanismos que rigen el desarrollo y organización de los órganos linfoides secundarios han sido descubiertos en la década pasada y, ayudan a concluir que las interacciones celulares y moleculares específicas para el desarrollo y organización de los órganos linfoides secundarios son ligeramente diferentes y reflejan probablemente la presencia de poblaciones celulares específicas en un lugar y tiempo adecuados. En esta revisión se discuten los mecanismos involucrados en el desarrollo, organización y función de tejidos linfoides locales del tracto respiratorio, incluidos el tejido linfoide asociado a la nariz (NALT) y el tejido linfoide inducible asociado al bronquio (iBALT)

Secondary lymphoid organs are strategically placed to recruit locally activated antigen presenting cells (APCs) as well as naïve, recirculating T and B cells. The structure of secondary lymphoid organs - separated B and T zones, populations of specialized stromal cells, high endothelial venules and lymphatic vessels - has also evolved to maximize encounters between APCs and lymphocytes and to facilitate the expansion and differentiation of antigen- stimulated T and B cells. Many of the general mechanisms that govern the development and organization of secondary lymphoid organs have been identified over the last decade. However, the specific cellular and molecular interactions involved in the development and organization of each secondary lymphoid organ are slightly different and probably reflect the cell types available at that time and location. Here we review the mechanisms involved in the development, organization and function of local lymphoid tissues in the respiratory tract, including Nasal Associated Lymphoid Tissue (NALT) and inducible Bronchus Associated Lymphoid Tissue (iBALT)

Effect of Staphylococcus enterotoxin B on the concurrent CD8(+) T cell response to influenza virus infection.

Bacterial superantigens have potent in vivo effects. Respiratory viral infections are often associated with secondary bacterial infections, raising the likelihood of exposure to bacterial superantigens after the initiation of the anti-viral immune response. In this study, the general and V beta-specific effects of exposure to Staphylococcal enterotoxin B (SEB) during influenza virus infection on both the ongoing acute and the subsequent recall CD8(+) T cell responses were analyzed, using the well-characterized murine influenza model system and tetrameric MHC/peptide reagents to directly identify virus-specific T cells. The results show that although superantigen exposure during the primary viral infection caused delayed viral clearance, there was remarkably little effect of SEB on the magnitude or TCR repertoire of the ongoing cytolytic T cell response or on the recall response elicited by secondary viral infection. Thus, despite the well-characterized immunomodulatory effects of SEB, there was surprisingly little interference with concurrent anti-viral immunity.