T-Cell Turnover Following Vaccination With MVA85A

Inclusion Criteria: * Healthy adult aged 18 to 50 years * Immunization with BCG greater than 12 months prior to enrolment in the study * Resident in or near Oxford for the duration of the study * Able and willing (in the investigator's opinion) to comply with all study requirements * Given written informed consent * Willing to allow the investigator to request medical information from, or discuss the volunteer's medical history with the volunteer's General Practitioner * Willing to allow the investigator to register volunteer details with a confidential database to prevent concurrent entry into clinical trials * For women only, willingness to practice continuous effective contraception during the study * Agreement to refrain from blood donation during the course of the study Exclusion Criteria: Participation in another research study involving an investigational product in the 30 days preceding enrolment, or planned use during the study period * Prior receipt of a recombinant MVA vaccine * Screening test suggesting the possibility of latent TB infection- i.e. Elispot positive (greater than 17 sfc/million PBMC) in any ESAT6 peptide or CFP10 peptide pool * Any clinically significant abnormal finding on screening blood tests or urinalysis (see Appendix B for guidance on study reference ranges) * Administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate * Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection; asplenia; recurrent severe infections and chronic (more than 14 days) immunosuppressant medication within the past 6 months (inhaled and topical steroids are allowed) * History of allergic disease or reactions likely to be exacerbated by any component of the vaccine, e.g. egg products * Any history of anaphylaxis * History of cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ) * History of serious psychiatric condition * Suspected or known current alcohol abuse as defined by an alcohol intake of greater than 42 units every week * Seropositive for hepatitis B surface antigen (HBsAg) or hepatitis C virus (antibodies to HCV) * Pregnancy, lactation or willingness/intention to become pregnant during the study * Any other chronic illness requiring hospital specialist supervision * Any other significant disease, disorder or finding, which, in the opinion of the investigator, may either put the volunteer at risk because of participation in the study, or may influence the result of the study, or the volunteer's ability to participate fully in the study