%0 Journal Article
%T Evaluation of novel Epstein-Barr virus-derived antigen formulations for monitoring virus-specific T cells in pediatric patients with infectious mononucleosis.
%A Fischer F
%A Mücke J
%A Werny L
%A Gerrer K
%A Mihatsch L
%A Zehetmaier S
%A Riedel I
%A Geisperger J
%A Bodenhausen M
%A Schulte-Hillen L
%A Hoffmann D
%A Protzer U
%A Mautner J
%A Behrends U
%A Bauer T
%A Körber N
%J Virol J
%V 21
%N 1
%D 2024 Jun 14
%M 38877590
%F 5.913
%R 10.1186/s12985-024-02411-0
%X <B>BACKGROUND: </B>Infection with the Epstein-Barr virus (EBV) elicits a complex T-cell response against a broad range of viral proteins. Hence, identifying potential differences in the cellular immune response of patients with different EBV-associated diseases or different courses of the same disorder requires interrogation of a maximum number of EBV antigens. Here, we tested three novel EBV-derived antigen formulations for their ability to reactivate virus-specific T cells ex vivo in patients with EBV-associated infectious mononucleosis (IM).<BR><B>METHODS: </B>We comparatively analyzed EBV-specific CD4+ and CD8+ T-cell responses to three EBV-derived antigen formulations in 20 pediatric patients during the early phase of IM: T-activated EBV proteins (BZLF1, EBNA3A) and EBV-like particles (EB-VLP), both able to induce CD4+ and CD8+ T-cell responses ex vivo, as well as an EBV-derived peptide pool (PP) covering 94 well-characterized CD8+ T-cell epitopes. We assessed the specificity, magnitude, kinetics, and functional characteristics of EBV-specific immune responses at two sequential time points (v1 and v2) within the first six weeks after IM symptom onset (Tonset).<BR><B>RESULTS: </B>All three tested EBV-derived antigen formulations enabled the detection of EBV-reactive T cells during the early phase of IM without prior T-cell expansion in vitro. EBV-reactive CD4+ and CD8+ T cells were mainly mono-functional (CD4+: mean 64.92%, range 56.15-71.71%; CD8+: mean 58.55%, range 11.79-85.22%) within the first two weeks after symptom onset (v1) with IFN-γ and TNF-secreting cells representing the majority of mono-functional EBV-reactive T cells. By contrast, PP-reactive CD8+ T cells were primarily bi-functional (>60% at v1 and v2), produced IFN-γ and TNF and had more tri-functional than mono-functional components. We observed a moderate correlation between viral load and EBNA3A, EB-VLP, and PP-reactive CD8+ T cells (rs = 0.345, 0.418, and 0.356, respectively) within the first two weeks after Tonset, but no correlation with the number of detectable EBV-reactive CD4+ T cells.<BR><B>CONCLUSIONS: </B>All three EBV-derived antigen formulations represent innovative and generic recall antigens suitable for monitoring EBV-specific T-cell responses ex vivo. Their combined use facilitates a thorough analysis of EBV-specific T-cell immunity and allows the identification of functional T-cell signatures linked to disease development and severity.