Tonsillar homing of Epstein-Barr virus-specific CD8 T cells
By Journal of Clinical Investigation
Aug 19, 2005, 13:54
In a study appearing online on August 18 in advance of print publication of the September 1 issue of the Journal of Clinical Investigation, Alan Rickinson and colleagues from University of Birmingham address the immunology of long-term oropharyngeal shedding of Epstein-Barr virus at a time when infection of circulating lymphocytes is well-controlled.
The authors used three groups of patients at different stages of infection, representing different positions of the virus-host balance: acute infectious mononucleosis (IM) patients undergoing primary infection, post-IM patients shortly after resolution of acute infection, and long-term asymptomatic virus carriers.
During the acute disease and shortly after its resolution, CD8+ T cells specific for virus replicative epitopes are not efficiently targeted to oropharyngeal sites of viral replication, coincident with prolonged viral shedding from these sites.
By contrast, responses to virus latent cycle epitopes begin to accumulate more quickly in the tonsil post-IM and the latent infection is more rapidly controlled. In long-term virus carriers where both lytic and latent infections have been reduced to very low levels, both types of virus-specific response are dramatically enriched in tonsils compared to blood.
Indeed, in healthy asymptomatic carriers total reactivities to defined EBV epitopes can account for up to 20% of the entire tonsillar CD8 population. The data suggest that efficient control of EBV infection requires appropriate CD8 T cell homing to oropharyngeal sites.
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