Human CD8+ T cell responses against five newly identified respiratory syncytial virus-derived epitopes

1 Division of Pediatrics, Wilhelmina Children's Hospital, University Medical Center, KE 04.133.1, PO Box 85500, 3508 AB Utrecht, The Netherlands 2 Division of Pulmonology and the Department of Experimental Immunology, Academic Medical Center, Amsterdam, The Netherlands 3 The Netherlands Vaccine Institute, Bilthoven, The Netherlands 4 Division of Clinical Immunology, Academic Medical Center, Amsterdam, The Netherlands Correspondence Grada M. van Bleek g.vanbleek{at}wkz.azu.nl CD8 + T lymphocytes play a major role in the clearance of respiratory syncytial virus (RSV) infections. To be able to study the primary CTL response in RSV-infected children, epitopes presented by a set of commonly used HLA alleles (HLA-A1, -A3, -B44 and -B51) were searched for. Five epitopes were characterized derived from the matrix (M), non-structural (NS2) and second matrix (M2) proteins of RSV. All epitopes were shown to be processed and presented by RSV-infected antigen-presenting cells. HLA-A1 tetramers for one of these epitopes derived from the M protein were constructed and used to quantify and phenotype the memory CD8 + T cell pool in a panel of healthy adult donors. In about 60 % of the donors, CD8 + T cells specific for the M protein could be identified. These cells belonged to the memory T cell subset characterized by expression of CD27 and CD28, and down-regulation of CCR7 and CD45RA. The frequency of tetramer-positive cells varied between 0·4 and 3 per 10 4 CD8 + T cells in PBMC of healthy asymptomatic adult donors.