Portal de Periódicos da CAPES

Protection from Respiratory Virus Infections Can Be Mediated by Antigen-Specific Cd4+ T Cells That Persist in the Lungs

2001; Rockefeller University Press; Volume: 193; Issue: 8 Linguagem: Inglês

10.1084/jem.193.8.981

1540-9538

Robert J. Hogan, Weimin Zhong, Edward J. Usherwood, Tres Cookenham, Alan D. Roberts, David L. Woodland,

Immunotherapy and Immune Responses

Although CD4+ T cells have been shown to mediate protective cellular immunity against respiratory virus infections, the underlying mechanisms are poorly understood. For example, although phenotypically distinct populations of memory CD4+ T cells have been identified in different secondary lymphoid tissues, it is not known which subpopulations mediate protective cellular immunity. In this report, we demonstrate that virus-specific CD4+ T cells persist in the lung tissues and airways for several months after Sendai virus infection of C57BL/6 mice. A large proportion of these cells possess a highly activated phenotype (CD44hi, CD62Llo, CD43hi, and CD25hi) and express immediate effector function as indicated by the production of interferon γ after a 5-h restimulation in vitro. Furthermore, intratracheal adoptive transfer of lung memory cells into β2m-deficient mice demonstrated that lung-resident virus-specific CD4+ T cells mediated a substantial degree of protection against secondary virus infection. Taken together, these data demonstrate that activated memory CD4+ T cells persisting at mucosal sites play a critical role in mediating protective cellular immunity.