BACKGROUND: The magnitude of specific CD8+ T cell reactivity responsible for vaccine-induced protection against smallpox infection has not yet been fully elucidated. Among other techniques, RT-PCR for the monitoring of cytokine release in effector T cells against tumor and viral antigens has demonstrated a novel promising method. OBJECTIVE: To determine the functional status of antigen specific CD8+ T cells in healthy participants before and 4 weeks after prophylactic vaccination (Lister strain) against smallpox using quantitative real-time PCR (qRT-PCR). STUDY DESIGN: Changes of interferon-gamma (IFNgamma) mRNA expression levels on short term ex vivo peptide antigen stimulation were measured. The corresponding specific CD8+ T cell reactivity was then displayed as CD8-normalized IFN-gamma levels (IFN-gamma/CD8 ratio). RESULTS: We found a 5-9 fold increase of CD8+ T cell reactivity in three out of four vaccinated individuals. The kinetics and strength determined in responders reveal a virus specific T cell effector repertoire pre-vaccination and a corresponding functional state after immunization comparable also to data obtained from tetramer- and ELISPOT analysis. CONCLUSIONS: Apart from protective vaccinia-specific neutralizing antibodies, the presence of antigen-specific CD8+ T-cells has been demonstrated after vaccinia vaccination. In concordance with others, results from this PCR-based study indicate that this smallpox vaccine induces strong vaccinia virus-specific CD8+ and IFN-gamma producing T cell responses.
BACKGROUND: The magnitude of specific CD8+ T cell reactivity responsible for vaccine-induced protection against smallpoxinfection has not yet been fully elucidated. Among other techniques, RT-PCR for the monitoring of cytokine release in effector T cells against tumor and viral antigens has demonstrated a novel promising method. OBJECTIVE: To determine the functional status of antigen specific CD8+ T cells in healthy participants before and 4 weeks after prophylactic vaccination (Lister strain) against smallpox using quantitative real-time PCR (qRT-PCR). STUDY DESIGN: Changes of interferon-gamma (IFNgamma) mRNA expression levels on short term ex vivo peptide antigen stimulation were measured. The corresponding specific CD8+ T cell reactivity was then displayed as CD8-normalized IFN-gamma levels (IFN-gamma/CD8 ratio). RESULTS: We found a 5-9 fold increase of CD8+ T cell reactivity in three out of four vaccinated individuals. The kinetics and strength determined in responders reveal a virus specific T cell effector repertoire pre-vaccination and a corresponding functional state after immunization comparable also to data obtained from tetramer- and ELISPOT analysis. CONCLUSIONS: Apart from protective vaccinia-specific neutralizing antibodies, the presence of antigen-specific CD8+ T-cells has been demonstrated after vaccinia vaccination. In concordance with others, results from this PCR-based study indicate that this smallpox vaccine induces strong vaccinia virus-specific CD8+ and IFN-gamma producing T cell responses.
Authors: Victoria O Kasprowicz; Jessica E Mitchell; Shivan Chetty; Pamla Govender; Kuan-Hsiang Gary Huang; Helen A Fletcher; Daniel P Webster; Sebastian Brown; Anne Kasmar; Kerry Millington; Cheryl L Day; Nompumelelo Mkhwanazi; Cheryl McClurg; Fundisiwe Chonco; Ajit Lalvani; Bruce D Walker; Thumbi Ndung'u; Paul Klenerman Journal: PLoS One Date: 2011-08-11 Impact factor: 3.240
Authors: Elke Schultz-Thater; Daniel M Frey; Daniela Margelli; Nermin Raafat; Chantal Feder-Mengus; Giulio C Spagnoli; Paul Zajac Journal: J Transl Med Date: 2008-10-16 Impact factor: 5.531