Real time PCR for the assessment of CD8+ T cellular immune response after prophylactic vaccinia vaccination.
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).


METHODS
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.
Trojan
A
A
Multidisciplinary Oncology Centre, Centre Hospitalier Universitaire Vaudois, CHUV, CH-1011 Lausanne, Switzerland. andtrojan@yahoo.de
Rajeswaran
R
R
Montemurro
M
M
Mütsch
M
M
Steffen
R
R
D000328:Adult; D000914:Antibodies, Viral / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000097:blood* / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation; D008297:Male; D016133:Polymerase Chain Reaction; D012899:Smallpox / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D012900:Smallpox Vaccine / Q000276:immunology*; D014611:Vaccination; D014615:Vaccinia / Q000276:immunology* / Q000821:virology
D000914:Antibodies, Viral; D000956:Antigens, Viral; D012900:Smallpox Vaccine; D007371:Interferon-gamma