Novel mumps virus epitopes reveal robust cytotoxic T cell responses after natural infection but not after vaccination

Abstract

Mumps is nowadays re-emerging despite vaccination. The contribution of T cell immunity to protection against mumps has not been clearly defined. Previously, we described a set of 41 peptides that were eluted from human leukocyte antigen (HLA) class I molecules of mumps virus (MuV)-infected cells. Here, we confirmed immunogenicity of five novel HLA-B*07:02- and HLA-A*01:01-restricted MuV T cell epitopes from this set of peptides. High frequencies of T cells against these five MuV epitopes could be detected ex vivo in all tested mumps patients. Moreover, these epitope-specific T cells derived from mumps patients displayed strong cytotoxic activity. In contrast, only marginal T cell responses against these novel MuV epitopes could be detected in recently vaccinated persons, corroborating earlier findings. Identifying which MuV epitopes are dominantly targeted in the mumps-specific CD8+ T- response is an important step towards better understanding in the discrepancies between natural infection or vaccination-induced cell-mediated immune protection.

Maintenance of the virus-specific CD8+ T-cell repertoire: Implications for vaccine strategies

“…Studies focusing on the T-cell response against mumps have mostly investigated the response after MuV-vaccination, however it is generally observed that vaccination-acquired immunity is not as efficient as the long term response induced after a natural infection [16,34,296]. This is also the case for the T-cell responses to MuV-vaccination and MuV-infection.…”