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

The purpose of this study is to examine the safety, reactogenicity and immunogenicity of the GlaxoSmithKline (GSK) Biologicals candidate pneumococcal vaccine containing PhtD in healthy elderly population aged 18-45 years of age.

The safety profile of the PhtD vaccine will be assessed in comparison to a comparator vaccine (Pneumovax 23TM). In order to further increase the immune response to vaccination, a novel adjuvant system will also be examined.

Eligibility Criteria:
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.