CMV pp65 and IE-1 T cell epitopes recognized by healthy subjects

BACKGROUND: Adoptive immune and vaccine therapies have been used to prevent cytomegalovirus (CMV) disease in recipients of hematopoietic progenitor cell transplants, but the nature of T cell responses to CMV have not been completely characterized. METHODS: Peptide pools and individual peptides derived from the immune-dominant CMV proteins pp65 and IE-1 and antigen-specific, cytokine flow cytometry were used to characterize the prevalence and frequency of CD4+ and CD8+ memory T cells in 20 healthy CMV-seropositive subjects. RESULTS: CD8+ T cell responses to pp65 were detected in 35% of subjects and to IE-1 in 40% of subjects. CD4+ T cell responses to pp65 were detected in 50% of subjects, but none were detected to IE-1. Several new IE-1 HLA class I epitopes were identified, including 4 restricted to HLA-C antigens. One region of IE-1 spanning amino acids 300 to 327 was rich in class I epitopes. The HLA class I restrictions of IE-1 peptides were more promiscuous than those of pp65 peptides. CONCLUSION: Since naturally occurring CD4+ and CD8+ T cell responses to pp65 were detectable in many subjects, but only CD8+ T cell responses to IE-1 were detected, pp65 may be better than IE-1 for use in vaccine and adoptive immune therapies

GM-CSF/IL-3/IL-5 receptor common β chain (CD131) expression as a biomarker of antigen-stimulated CD8+ T cells

<p>Abstract</p> <p>Background</p> <p>Upon Ag-activation cytotoxic T cells (CTLs) produce IFN-γ GM-CSF and TNF-α, which deliver simultaneously pro-apoptotic and pro-inflammatory signals to the surrounding microenvironment. Whether this secretion affects in an autocrine loop the CTLs themselves is unknown.</p> <p>Methods</p> <p>Here, we compared the transcriptional profile of Ag-activated, Flu-specific CTL stimulated with the FLU M1:58-66 peptide to that of convivial CTLs expanded <it>in vitro </it>in the same culture. PBMCs from 6 HLA-A*0201 expressing donors were expanded for 7 days in culture following Flu M1:58-66 stimulation in the presence of 300 IU/ml of interleukin-2 and than sorted by high speed sorting to high purity CD8+ expressing T cells gated according to FluM1:58-66 tetrameric human leukocyte antigen complexes expression.</p> <p>Results</p> <p>Ag-activated CTLs displayed higher levels of IFN-γ, GM-CSF (CSF2) and GM-CSF/IL-3/IL-5 receptor common β- chain (CD131) but lacked completely expression of IFN-γ receptor-II and IFN-stimulated genes (ISGs). This observation suggested that Ag-activated CTLs in preparation for the release of IFN-γ and GM-CSF shield themselves from the potentially apoptotic effects of the former entrusting their survival to GM-SCF. <it>In vitro </it>phenotyping confirmed the selective surface expression of CD131 by Ag-activated CTLs and their increased proliferation upon exogenous administration of GM-CSF.</p> <p>Conclusion</p> <p>The selective responsiveness of Ag-activated CTLs to GM-CSF may provide an alternative explanation to the usefulness of this chemokine as an adjuvant for T cell aimed vaccines. Moreover, the selective expression of CD131 by Ag-activated CTLs proposes CD131 as a novel biomarker of Ag-dependent CTL activation.</p

GM-CSF/IL-3/IL-5 receptor common β chain (CD131) expression as a biomarker of antigen-stimulated CD8T cells-0

(red bar) CD8 T cells at a test p-value < 0.001 whose annotation includes the word "interferon". The table displays the gene symbol, its name and the level of differential expression (Δ) as the CY5/CY3 ratio of fly-specific versus convivial in green and vice versa in red.<p><b>Copyright information:</b></p><p>Taken from "GM-CSF/IL-3/IL-5 receptor common β chain (CD131) expression as a biomarker of antigen-stimulated CD8T cells"</p><p>http://www.translational-medicine.com/content/6/1/17</p><p>Journal of Translational Medicine 2008;6():17-17.</p><p>Published online 15 Apr 2008</p><p>PMCID:PMC2330025.</p><p></p