Study to Evaluate the Safety, Reactogenicity and Immunogenicity of GlaxoSmithKline (GSK) Biologicals' Investigational Respiratory Syncytial Virus (RSV) Vaccines

Inclusion Criteria: * Subjects who, in the opinion of the investigator, can and will comply with the requirements of the protocol. * Written informed consent obtained from the subject. * A male between, and including, 18 and 44 years of age at the time of vaccination. * Healthy subjects as established by medical history and clinical examination before entering into the study. Exclusion Criteria: * Use of any investigational or non-registered product other than the study vaccines within 30 days preceding the dose of study vaccine, or planned use during the study period. * Concurrently participating in another clinical study, at any time during the study period, in which the subject has been or will be exposed to an investigational or a non-investigational vaccine/product. * Planned administration/ administration of a vaccine not foreseen by the study protocol within the period starting 30 days before and ending 30 days after vaccination, with the exception of any licensed influenza vaccine which may be administered ≥ 15 days before or after vaccination. * Previous vaccination against RSV. * Chronic administration of immunosuppressants or other immune-modifying drugs within 6 months prior to the vaccine dose. Inhaled and topical steroids are allowed. * Administration of long-acting immune-modifying drugs at any time during the study period. * Administration of immunoglobulins and/or any blood products within the 3 months preceding the dose of study vaccine or planned administration during the study period. * Any confirmed or suspected immunosuppressive or immunodeficient condition, based on medical history and physical examination. * Family history of congenital or hereditary immunodeficiency. * History of or current autoimmune disease. * History of any reaction or hypersensitivity likely to be exacerbated by any component of the vaccines. * Hypersensitivity to latex. * Any clinically significant hematological (hemoglobin level, white blood cell \[WBC\], lymphocyte, neutrophil, eosinophil and platelet count) and biochemical (alanine aminotransferase \[ALT\], aspartate aminotransferase \[AST\] and creatinine) abnormality as per the opinion of the investigator, based on the local laboratory normal ranges. * Subjects with hematological/ biochemical values out of normal range which are expected to be temporary may be re-screened at a later date. * Any acute or chronic, clinically significant disease, as determined by physical examination or laboratory screening tests. * Malignancies within previous 5 years (excluding non-melanoma skin cancer) and lymphoproliferative disorders. * Current alcoholism and/or drug abuse. * Acute disease and/or fever at the time of Screening. * Fever is defined as temperature ≥ 37.5°C /99.5°F for oral, axillary or tympanic route, or ≥ 38.0°C /100.4°F on rectal route. The preferred route for recording temperature in this study will be oral. * Subjects with a minor illness (such as mild diarrhea) without fever may be enrolled at the discretion of the investigator. * Subjects with acute disease and/ or fever at the time of Screening may be re screened at a later date. * Planned move to a location that will prohibit participating in the trial until study end. * Any other condition that the investigator judges may interfere with study procedures (e.g. drawing blood) or findings (e.g. immune response).