Background: Although human airway epithelial cells are the main target of respiratory syncytial virus (RSV), it also infects immune cells, such as macrophages and B cells. Whether T cells are permissive to RSV infection is unknown. We sought to analyze the permissiveness of CD4+ T cells to RSV infection.
Methods: CD4+ and CD8+ T cells from cord blood, healthy young children, and adults were challenged by RSV or cocultured with infected HEp-2 cells. Infection, phenotype, and cytokine production by T cells were analyzed by flow cytometry or enzyme-linked immunosorbent assay. Expression of RSV antigens by circulating CD4+ T cells from infected children was analyzed by flow cytometry, and disease severity was defined by standard criteria.
Results: CD4+ and CD8+ T cells were productively infected by RSV. Infection decreased interleukin 2 and interferon γ production as well as the expression of CD25 and Ki-67 by activated CD4+ T cells. Respiratory syncytial virus antigens were detected in circulating CD4+ and CD8+ T cells during severe RSV infection of young children. Interestingly, the frequency of CD4+ RSV+ T cells positively correlated with disease severity.
Conclusions: Respiratory syncytial virus infects CD4+ and CD8+ T cells and compromises T-cell function. The frequency of circulating CD4+ RSV+ T cells might represent a novel marker of severe infection.
Keywords: CD4+ T cells; bronchiolitis; infants; interferon γ; interleukin 2; markers of disease severity.; respiratory syncytial virus; viral infection.
© The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: [email protected].