Memory generation and maintenance of CD8+ T cell function during viral persistence

SS Cush, KM Anderson, DH Ravneberg… - The Journal of …, 2007 - journals.aai.org
SS Cush, KM Anderson, DH Ravneberg, JL Weslow-Schmidt, E Flaño
The Journal of Immunology, 2007journals.aai.org
During infection with viruses that establish latency, the immune system needs to maintain
lifelong control of the infectious agent in the presence of persistent Ag. By using a γ-
herpesvirus (γHV) infection model, we demonstrate that a small number of virus-specific
central-memory CD8+ T cells develop early during infection, and that virus-specific CD8+ T
cells maintain functional and protective capacities during chronic infection despite low-level
Ag persistence. During the primary immune response, we show generation of CD8+ memory …
Abstract
During infection with viruses that establish latency, the immune system needs to maintain lifelong control of the infectious agent in the presence of persistent Ag. By using a γ-herpesvirus (γHV) infection model, we demonstrate that a small number of virus-specific central-memory CD8+ T cells develop early during infection, and that virus-specific CD8+ T cells maintain functional and protective capacities during chronic infection despite low-level Ag persistence. During the primary immune response, we show generation of CD8+ memory T cell precursors expressing lymphoid homing molecules (CCR7, L-selectin) and homeostatic cytokine receptors (IL-7α, IL-2/IL-15β). During long-term persistent infection, central-memory cells constitute 20–50% of the virus-specific CD8+ T cell population and maintain the expression of L-selectin, CCR7, and IL-7R molecules. Functional analyses demonstrate that during viral persistence: 1) CD8+ T cells maintain TCR affinity for peptide/MHC complexes, 2) the functional avidity of CD8+ T cells measured as the capacity to produce IFN-γ is preserved intact, and 3) virus-specific CD8+ T cells have in vivo killing capacity. Next, we demonstrate that at 8 mo post-virus inoculation, long-term CD8+ T cells are capable of mediating a protective recall response against the establishment of γHV68 splenic latency. These observations provide evidence that functional CD8+ memory T cells can be generated and maintained during low-load γHV68 persistence.
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