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Clinical and Developmental Immunology
Volume 2013, Article ID 989673, 11 pages
Research Article

PD-L1 Expression Induced by the 2009 Pandemic Influenza A(H1N1) Virus Impairs the Human T Cell Response

1Medical Research Unit on Immunochemistry (UIMIQ), Specialties Hospital, National Medical Centre “Siglo XXI,” Mexican Social Security Institute (IMSS), 06720 México, DF, Mexico
2Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, 11340 México, DF, Mexico
3Facultad de Química, Universidad Nacional Autónoma de México, 04510 México, DF, Mexico
4Unidad de Investigación en Epidemiología Clínica, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social (IMSS), 06720 México, DF, Mexico
5Instituto Nacional de Salud Pública, 62100 Cuernavaca, MOR, Mexico

Received 8 July 2013; Accepted 22 August 2013

Academic Editor: Oscar Bottasso

Copyright © 2013 Nuriban Valero-Pacheco et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


PD-L1 expression plays a critical role in the impairment of T cell responses during chronic infections; however, the expression of PD-L1 on T cells during acute viral infections, particularly during the pandemic influenza virus (A(H1N1)pdm09), and its effects on the T cell response have not been widely explored. We found that A(H1N1)pdm09 virus induced PD-L1 expression on human dendritic cells (DCs) and T cells, as well as PD-1 expression on T cells. PD-L1 expression impaired the T cell response against A(H1N1)pdm09 by promoting CD8+ T cell death and reducing cytokine production. Furthermore, we found increased PD-L1 expression on DCs and T cells from influenza-infected patients from the first and second 2009 pandemic waves in Mexico City. PD-L1 expression on CD8+ T cells correlated inversely with T cell proportions in patients infected with A(H1N1)pdm09. Therefore, PD-L1 expression on DCs and T cells could be associated with an impaired T cell response during acute infection with A(H1N1)pdm09 virus.