Group identifies HHV-6B-specific CD8+ T Cell response
A new study from the University of Munchen in Munich, Germany, has identified a subset of CD8+ T cells that specifically recognize HHV-6B and not HHV-6A. The group is led by Dr. Andreas Moosman, who presented preliminary findings at the 7th International Conference on HHV-6 & 7 in 2011. Their work demonstrates that a specific class of CD8+ T cells recognizes HLA-A2-restricted peptides from the viral structural proteins U54 and U11, and displays several antigen-specific antiviral effector functions. HHV-6B-infected primary CD4+ T cells are recognized by these CD8+ T cells in an HLA-restricted manner, and furthermore produce antiviral cytokines, which contribute to the effective killing of infected cells. HHV-6A infected cells, on the other hand, are not recognized by the CD8+ T cells.
Importantly, this finding suggests that future immunotherapies could be aimed at minimizing the affects of HHV-6B-associated disease through taking advantage of these newly characterized virus-specific CD8+ T cell responses. As recent studies (Tormo et al, others) have indicated that lymphopenia-associated deficiencies in T cells specific for either HHV-6 or CMV can lead to the reactivation of both viruses in immunosuppressed patients, the reconstitution of antigen-specific T cells specific for HHV-6B may also serve as an effective therapeutic strategy for limiting the affects of CMV or EBV in these patients as well.