Two antigenic peptides from genes m123 and m164 of murine cytomegalovirus quantitatively dominate CD8 T-cell memory in the H-2d haplotype.
The importance of CD8 T cells for the control of cytomegalovirus (CMV) infection has raised interest in the identification of immunogenic viral proteins as candidates for vaccination and cytoimmunotherapy. The final aim is to determine the viral "immunome" for any major histocompatibility complex class I molecule by antigenicity screening of proteome-derived peptides. For human CMV, there is a limitation to this approach: the T cells used as responder cells for peptide screening are usually memory cells that have undergone in vivo selection. On this basis, pUL83 (pp65) and pUL123 (IE1 or pp68 to -72) were classified as immunodominant proteins. It is an open question whether this limited "memory immunome" really reflects the immunogenic potential of the human CMV proteome. Here we document an analogous focus of the memory repertoire on two proteins of murine CMV. Specifically, ca. 80% of all memory CD8 T cells in the spleen as well as in persisting pulmonary infiltrates were found to be specific for the known IE1 peptide 168YPHFMPTNL176 and for the peptide 257AGPPRYSRI265, newly defined here, derived from open reading frame m164. Notably, CD8 T-cell lines of both specificities protected against acute infection upon adoptive transfer. In contrast, the natural immune response to acute infection in draining lymph nodes and in the lungs indicated a somewhat broader specificity repertoire. We conclude that the low number of antigenic peptides identified so far for CMVs reflects a focused memory repertoire, and we predict that more antigenic peptides will be disclosed by analysis of the acute immune response.
Holtappels
Rafaela
R
Institute for Virology, Johannes Gutenberg University, 55101 Mainz, Germany.
Thomas
Doris
D
Podlech
Jürgen
J
Reddehase
Matthias J
MJ
D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D006183:H-2 Antigens / Q000235:genetics*; D006239:Haplotypes; D006566:Herpesviridae Infections / Q000276:immunology*; D017874:Immediate-Early Proteins / Q000276:immunology*; D007156:Immunologic Memory; D051379:Mice; D008807:Mice, Inbred BALB C; D018146:Muromegalovirus / Q000276:immunology*; D016366:Open Reading Frames; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology; D010750:Phosphoproteins / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D014763:Viral Matrix Proteins / Q000276:immunology*; D014764:Viral Proteins
D000956:Antigens, Viral; D006183:H-2 Antigens; C088645:IE1 protein, cytomegalovirus; D017874:Immediate-Early Proteins; D010446:Peptide Fragments; D010750:Phosphoproteins; D014763:Viral Matrix Proteins; D014764:Viral Proteins; C065418:cytomegalovirus matrix protein 65kDa