Study to Evaluate Safety, Reactogenicity and Immunogenicity of the Pneumococcal Protein PhtD Vaccine in Healthy Adults

Inclusion Criteria: * Subjects who the investigator believes will comply with the requirements of the protocol should be enrolled in the study. * A male or female between, and including, 18 and 45 years at the time of the first vaccination. * Written informed consent obtained from the subject. * Free of obvious health problems as established by medical history and clinical examination before entering into the study. * If the subject is female, she must be of non-childbearing potential, i.e., either surgically sterilized or one year post-menopausal; or, if of childbearing potential, she must be abstinent or have used adequate contraceptive precautions for 30 days prior to vaccination, have a negative pregnancy test and must agree to continue such precautions for two months after completion of the vaccination series. Exclusion Criteria: * Use of any investigational or non-registered product other than the study vaccine(s) within 30 days preceding the first dose of study vaccine, or planned use during the study period or participation to another pharmaceutical/vaccine study. * Chronic administration of immunosuppressants or other immune-modifying drugs within six months prior to the first vaccine dose. * Use of any anticoagulants. * Planned administration/ administration of a vaccine not foreseen by the study protocol within 2 weeks of the first dose of vaccines. * Previous vaccination against Streptococcus pneumoniae. * Bacterial pneumonia within 3 years prior to 1st vaccination. * Any confirmed or suspected immunosuppressive or immunodeficient condition, including human immunodeficiency virus (HIV) infection. * History of allergic disease or reactions likely to be exacerbated by any component of the vaccine. * Current serious neurologic or mental disorders. * Inflammatory processes such as known chronic active infections. * All malignancies (excluding non-melanic skin cancer) and lymphoproliferative disorders diagnosed or treated actively during the past 5 years. * History of administration of an experimental vaccine containing 3-deacylated Monophosphoryl Lipid A (MPL) or Quillaja saponaria 21 (QS21). * Acute disease at the time of enrolment. All vaccines can be administered to persons with a minor illness such as diarrhea, mild upper respiratory infection with or without low-grade febrile illness, i.e., Oral temperature \<37.5°C or Axillary temperature \<37.5°C. * Acute or chronic, clinically significant pulmonary, cardiovascular, hepatic or renal functional abnormality, as determined by physical examination or laboratory screening tests, at the discretion of the investigator. * Pregnant or lactating female. * History of chronic alcohol consumption and/or intravenous drug abuse.