Aged mice exhibit a severely diminished CD8 T cell response following respiratory syncytial virus infection.
Respiratory virus infections in the elderly result in increased rates of hospitalization and death. Respiratory syncytial virus (RSV) is a leading cause of severe virus-induced respiratory disease in individuals over the age of 65. CD8 T cells play a critical role in mediating RSV clearance. While it is clear that T cell immunity declines with age, it is not clear to what extent the CD8 T cell response to RSV is altered. Using aged BALB/c mice, we demonstrated that RSV-specific CD8 T cell responses were significantly reduced in the lungs of aged mice at the peak of the T cell response and that this decrease correlated with delayed viral clearance. Despite a decrease in the overall numbers of RSV-specific CD8 T cells during acute infection, their capacity to produce effector cytokines was not impaired. Following viral clearance, the RSV-specific memory CD8 T cells were similar in total number and phenotype in young and aged mice. Furthermore, following infection with a heterologous pathogen expressing an RSV epitope, RSV-specific memory CD8 T cells exhibited similar activation and ability to provide early control of the infection in young and aged mice. These data demonstrate a decrease in the capacity of aged mice to induce a high-magnitude acute CD8 T cell response, leading to prolonged viral replication, which may contribute to the increased disease severity of RSV infection observed for aged individuals.
Department of Microbiology.
Ross B
RB
Fulton
Kayla A
KA
Weiss
Lecia L
LL
Pewe
John T
JT
Harty
Steven M
SM
Varga
D000375:Aging / Q000276:immunology*; D000818:Animals; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D015536:Down-Regulation; D005260:Female; D006801:Humans; D008168:Lung / Q000276:immunology / Q000821:virology; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology* / Q000821:virology; D012136:Respiratory Syncytial Viruses / Q000276:immunology / Q000502:physiology*; D018418:Th2 Cells / Q000276:immunology