Identification of a Common HLA-DP4-Restricted T-Cell Epitope in the Conserved Region of the Respiratory Syncytial Virus G Protein

Abstract

The cellular immune response to respiratory syncytial virus (RSV) is important in both protection and immunopathogenesis. In contrast to HLA class I, HLA class II-restricted RSV-specific T-cell epitopes have not been identified. Here, we describe the generation and characterization of two human RSV-specific CD4؉ -T-cell clones (TCCs) associated with type 0-like cytokine profiles. TCC 1 was specific for the matrix protein and restricted over HLA-DPB1*1601, while TCC 2 was specific for the attachment protein G and restricted over either HLA-DPB1*0401 or -0402. Interestingly, the latter epitope is conserved in both RSV type A and B viruses. Given the high allele frequencies of HLA-DPB1*0401 and -0402 worldwide, this epitope could be widely recognized and boosted by recurrent RSV infections. Indeed, peptide stimulation of peripheral blood mononuclear cells from healthy adults resulted in the detection of specific responses in 8 of 13 donors. Additional G-specific TCCs were generated from three of these cultures, which recognized the identical (n ‫؍‬ 2) or almost identical (n ‫؍‬ 1) HLA-DP4-restricted epitope as TCC 2. No significant differences were found between the capacities of cell lines obtained from infants with severe (n ‫؍‬ 41) or mild (n ‫؍‬ 46) RSV lower respiratory tract infections to function as antigen-presenting cells to the G-specific TCCs, suggesting that the severity of RSV disease is not linked to the allelic frequency of HLA-DP4. In conclusion, we have identified an RSV G-specific human T helper cell epitope restricted by the widely expressed HLA class II alleles DPB1*0401 and -0402. Its putative role in protection and/or immunopathogenesis remains to be determined. Respiratory syncytial virus (RSV), a member of the genusPneumovirus of the family Paramyxoviridae, is a major cause of severe lower respiratory tract disease in infants, immunocompromised individuals, and the elderly (7, 29). RSV infections cause yearly epidemics in the winter season of moderate climate zones and are most often associated with relatively mild upper respiratory tract infections (29). In general, specific immunity is insufficient for protection, and RSV infections continue to occur throughout life.At present, no licensed RSV vaccine is available. During vaccine trials in the 1960s, vaccination with a formalin-inactivated whole-virus preparation (FI-RSV) was found to predispose for enhanced clinical disease following natural infection with RSV (17). Although the exact mechanism of this apparently immunopathological phenomenon remains unclear, studies of both rodent and nonhuman primate models have suggested that a skewed RSV-specific T helper type 2 (Th2) response was a key factor in this process (11,23). Several studies have suggested that primary infections in young infants resulting in severe RSV bronchiolitis are also associated with Th2 responses (24, 28). However, in two other cohort studies of infants with either severe RSV bronchiolitis or relatively mild RSV upper respiratory tract infection, this observation was...

HLA-associated susceptibility to childhood B-cell precursor ALL: definition and role of HLA-DPB1 supertypes

“…RSV is a highly contagious, weakly pathogenic, but strongly immunogenic virus that is widely distributed in the childhood population (Handforth et al, 2000;McNamara and Smyth, 2002). The G protein of RSV elicits CD4 þ T-cell responses (De Graaf et al, 2004;De Waal et al, 2004), the peptide 162 D-N 179 containing two overlapping T-cell epitopes, 163 FHFEVFNFV 171 and 165 FEVFNFVPC 173 that are restricted by DPB1*0401 (DP4), and DPB1*0201 (DP2) (De Graaf et al, 2004). Both peptides have F at P1 and P6 suggestive of binding to GEG (DP2) and GKG (DP4), consistent with the association of BCP ALL with DP2/DP4.…”

“…We and others have previously reported associations between DP alleles and human leukaemia (Pawelec et al, 1988;Taylor et al, 1995Taylor et al, , 2002. Furthermore, DP alleles are known to be associated with, or to act as restriction elements for a number of parasitic (Meyer et al, 1994;May et al, 1998), microbial and viral diseases, including hepatitis B and rabies (Celis and Karr, 1989;Celis et al, 1990), herpes simplex (Koelle et al, 2000), streptococcus (Dong et al, 1995), dengue virus (Kurane et al, 1993;Okamoto et al, 1998), Epstein -Barr virus (Voo et al, 2002), respiratory syncytial virus (RSV) (De Graaf et al, 2004;De Waal et al, 2004), and HIV (Cohen et al, 2006).…”

Selective retention of herpes simplex virus-specific T cells in latently infected human trigeminal ganglia

“…The antigen-specificity of TCLs was determined in an IFN-␥ ELISPOT assay, as described in ref. 48, using 10 4 T cells and 2 ϫ 10 4 APCs per well. Spots were counted with an automated ELISPOT reader (Sanquin, Amsterdam, The Netherlands).…”

Structural and Nonstructural Viral Proteins Are Targets of T-Helper Immune Response against Human Respiratory Syncytial Virus

“…In contrast, only one published study attempted to elucidate the possible array of HRSV ligands that are restricted by HLA class II molecules in two different patients (9). These CD4 ϩ T cells, which were restricted by two HLA-DP alleles, were specific for two peptides from the matrix and attachment G proteins, respectively (9).…”

“…However, these experiments were performed with overlapping synthetic pep-tides against only the F protein (6, 7) or a short fragment of 21 residues from the G protein (8). In contrast, only one published study attempted to elucidate the possible array of HRSV ligands that are restricted by HLA class II molecules in two different patients (9). These CD4 ϩ T cells, which were restricted by two HLA-DP alleles, were specific for two peptides from the matrix and attachment G proteins, respectively (9).…”