Determining the Breadth of the Respiratory Syncytial Virus-Specific T Cell Response

Abstract

Respiratory syncytial virus (RSV) is the most common cause of viral lower respiratory tract infections in infants and children under the age of 5. Studies examining RSV infection in susceptible BALB/c mice indicate that both CD4 and CD8 T cells not only contribute to viral clearance but also facilitate RSV-induced disease. However, efforts to understand the mechanisms by which RSV-specific T cells mediate disease following acute RSV infection have been hampered by the lack of defined RSV-specific T cell epitopes. Using an overlapping peptide library spanning each of the RSV-derived proteins, intracellular cytokine staining for gamma interferon was utilized to identify novel RSV-specific CD4 and CD8 T cell epitopes. Five novel CD8 T cell epitopes were revealed within the RSV fusion (F) protein and glycoprotein (G). In addition, five previously unidentified CD4 T cell epitopes were discovered, including epitopes in the phosphoprotein (P), polymerase protein (L), M2-1 protein, and nucleoprotein (N). Though the initial CD4 T cell epitopes were 15 amino acids in length, synthesis of longer peptides increased the frequency of responding CD4 T cells. Our results indicate that CD4 T cell epitopes that are 17 amino acids in length result in more optimal CD4 T cell stimulation than the commonly used 15-mer peptides. IMPORTANCE Respiratory syncytial virus (RSV) is the leading cause of hospitalization for lower respiratory tract infection in children. T cells play a critical role in clearing an acute RSV infection, as well as contributing to RSV-induced disease.Here we examined the breadth of the RSV-specific T cell response, using for the first time an overlapping peptide library spanning the entire viral genome. We identified 5 new CD4 and 5 new CD8 T cell epitopes, including a CD8 T cell epitope within the G protein that was previously believed not to elicit a CD8 T cell response. Importantly, we also demonstrated that the use of longer, 17-mer peptides elicits a higher frequency of responding CD4 T cells than the more commonly used 15-mer peptides. Our results demonstrate the breadth of the CD4 and CD8 T cell response to RSV and demonstrate the importance of using longer peptides when stimulating CD4 T cell responses. R espiratory syncytial virus (RSV), a single-stranded negativesense RNA paramyxovirus, is the leading cause of hospitalizations for lower respiratory tract infections in young children (1). RSV is a ubiquitous pathogen, infecting 30 to 60% of children during their first year of life and up to 90% of children by their second year of life (2-4). Furthermore, approximately 3% of RSVinfected children require hospitalization (5). In total, it is estimated that worldwide, RSV is responsible for 3.4 million acute lower respiratory tract infections annually in children under the age of 5, resulting in up to 196,000 yearly fatalities (6). In addition to children, the elderly are also susceptible to severe RSV-induced disease (7).BALB/c mice are susceptible to RSV infection and have been used extensively to ...

Surface expression of the hRSV nucleoprotein impairs immunological synapse formation with T cells

“…Nevertheless, whether N protein may also interfere with the cytolytic function of CD8 + Cytotoxic T Lymphocytes (CTLs) remains to be evaluated. This aspect is of special relevance considering that several circulating CTL clones that are specific for hRSV antigens (including the N protein) have been identified in adults (53)(54)(55)(56). Because circulating memory CD8 + T cells rapidly differentiate into effector CTLs (57,58), the presence and effector function shown by these CTLs further support the notion that antigen-experienced T cells are less susceptible to inhibition by the hRSV.…”

CD8 T-Cell Response to Respiratory Syncytial Virus Infection

“…Fortunately, numerous CD8 T-cell epitopes have been identified in both BALB/c [37,[49][50][51][52][53] and C57BL/6 [45,54] mice as well as in humans [46,[55][56][57][58] (Table 1). In BALB/c mice, the immunodominant M2 82-90 epitope is often used in studies given the high frequency of CD8 T cells that are specific to this epitope following an acute RSV infection [37].…”

Hepatitis E virus ORF 1 induces proliferative and functional T‐cell responses in patients with ongoing and resolved hepatitis E

“…Investigating virus‐specific T‐cell responses against non‐structural proteins is of interest since this part of the virus genome can also be immunogenic and studies for vaccine development against human immunodeficiency virus (HIV) and hepatitis C virus (HCV) have shown the importance of a broad and multifunctional anti‐viral T‐cell response for virus clearance . For most viruses, T‐cell responses against the entire genome have been described . HCV‐specific T‐cell responses target proteins encoded by the entire HCV genome with no major preferences to specific HCV proteins, whereas in HIV infection T‐cell responses are more frequently detected against p24‐Gag and Nef …”