Identification of cytomegalovirus-specific cytotoxic T lymphocytes in vitro is greatly enhanced by the use of recombinant virus lacking the US2 to US11 region or modified vaccinia virus Ankara expressing individual viral genes.
Cytomegalovirus (CMV) elicits a potent T-cell response in humans that appears to protect the host from virus-associated disease. Despite facing strong host defense mechanisms, CMV remains as a lifelong infection that may reactivate and cause life-threatening disease in immunocompromised individuals. This persistence is probably assisted by expression of immune subversion proteins of the virus encoded by genes belonging to the US gene family. These proteins modulate major histocompatibility complex expression in infected cells and bias in vitro experiments toward the detection of only certain specificities. We have combined the use of recombinant CMV, lacking the US2 to US11 region genes, and cytoplasmic gamma interferon staining to define a more accurate assessment of CMV-specific responses in vivo. Recombinant CMV stimulation reveals a CD8 response much larger than that of parental virus in all donors tested. In some cases, this represented up to 10-fold increases in the number of cells detected. Responses were directed mainly against pp65, IE-1, and pp50 in the majority of donors. In addition, previously unreported IE-2-specific T-cell responses could be detected in a minority of cases. Furthermore, we observed a less marked increase in the response to mutant CMV by CD4 T cells in some donors. This suggests that a much broader T-cell response to CMV exists in vivo than is revealed by restimulation with wild-type virus and adds to the evidence that the efficacy of immune evasion strategies may not be as absolute as previously believed.
Khan
Naeem
N
CR UK Institute for Cancer Studies, Vincent Dr., Edgbaston, University of Birmingham, Birmingham B15 2TA, United Kingdom.
Bruton
Rachel
R
Taylor
Graham S
GS
Cobbold
Mark
M
Jones
Thomas R
TR
Rickinson
Alan B
AB
Moss
Paul A H
PA
D001483:Base Sequence; D003587:Cytomegalovirus / Q000235:genetics* / Q000276:immunology* / Q000472:pathogenicity; D004279:DNA, Viral / Q000235:genetics; D017353:Gene Deletion; D005814:Genes, Viral; D006801:Humans; D017874:Immediate-Early Proteins / Q000235:genetics / Q000276:immunology; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000096:biosynthesis; D008213:Lymphocyte Activation; D005810:Multigene Family; D010750:Phosphoproteins / Q000235:genetics / Q000276:immunology; D016601:RNA-Binding Proteins / Q000235:genetics; D011995:Recombination, Genetic; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014616:Vaccinia virus / Q000235:genetics / Q000276:immunology; D014759:Viral Envelope Proteins / Q000235:genetics; D014763:Viral Matrix Proteins / Q000235:genetics / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology
D004279:DNA, Viral; C088645:IE1 protein, cytomegalovirus; D017874:Immediate-Early Proteins; D010750:Phosphoproteins; D016601:RNA-Binding Proteins; C074546:US11 protein, herpesvirus; C118670:US2 protein, Varicellovirus; D014759:Viral Envelope Proteins; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C464963:pp67 protein, human cytomegalovirus; D007371:Interferon-gamma