A Study to Evaluate the Safety and Immunogenicity of an A/California/7/2009 (H1N1)V-like Vaccine GSK2340274A or GSK2340273A Co-administered With Trivalent Inactivated Seasonal Influenza Vaccine in Adults 19 to 40 Years of Age.

Inclusion Criteria:

- Subjects who the investigator believes can and will comply with the requirements of
the protocol.

- Written informed consent obtained from the subject.

- Male or female adults, 19-40 years of age at the time of the first vaccination.

- Safety laboratory tests results within the parameters specified in the protocol.

- Satisfactory baseline medical assessment by physical examination.

- Comprehension of the study requirements, ability to comprehend and comply with
procedures for collection of safety data, expressed availability for the required
study period, and ability and willingness to attend scheduled visits as documented by
signature on the informed consent document.

- Access to a consistent means of telephone contact, which may be either in the home or
at the workplace, land line, or mobile, but NOT a pay phone or other multiple-user
device.

- Female subjects of non-childbearing potential may be enrolled in the study.

- Female subjects of childbearing potential may be enrolled in the study, if the
subject:

- has practiced adequate contraception for 30 days prior to vaccination, and

- has a negative pregnancy test on the day of first vaccination, and

- has agreed to continue adequate contraception during the entire treatment period and
for 2 months after completion of the vaccination series.

Exclusion Criteria:

- Previous vaccination with an H1N1v-like virus vaccine or a medical history of
physician-confirmed infection with an H1N1v-like virus.

- Prior receipt at any time of any seasonal influenza vaccine.

- Planned administration of any vaccine not foreseen by the study protocol between Day
0 and the Day 63 phlebotomy.

- Administration of any licensed vaccine within 4 weeks before the first study vaccine
dose.

- Use of any investigational or non-registered product other than the study vaccines
within 30 days preceding the first dose of study vaccine, or planned use during the
study period.

- Receipt of systemic glucocorticoids within one month prior to study enrolment, or
any other cytotoxic or immunosuppressive drug within six months of study enrolment.
Topical, intra-articularly injected, or inhaled glucocorticoids, topical calcineurin
inhibitors or imiquimod are allowed.

- Receipt of any immunoglobulins and/or any blood products within three months of study
enrolment or planned administration of any of these products during the study period.

- Presence of evidence of substance abuse or of neurological or psychiatric diagnoses
which, even if stable, are deemed by the investigator to render the potential subject
unable/unlikely to provide accurate safety reports.

- Presence of a temperature >= 38.0ºC (>=100.4ºF), or acute symptoms greater than
"mild" severity on the scheduled date of first vaccination.

- Diagnosed with cancer, or treatment for cancer, within 3 years.

- Any confirmed or suspected immunosuppressive or immunodeficient condition, based on
medical history and physical examination.

- Any significant disorder of coagulation or treatment with warfarin derivatives or
heparin. Persons receiving individual doses of low molecular weight heparin outside
of 24 hours prior to vaccination are eligible. Persons receiving prophylactic
antiplatelet medications, e.g., low-dose acetylsalicylic acid, and without a
clinically-apparent bleeding tendency, are eligible.

- An acute evolving neurological disorder or history of Guillain-Barré syndrome within
six weeks of receipt of seasonal influenza vaccine.

- Any known or suspected allergy to any constituent of influenza vaccines; a history of
anaphylactic-type reaction to any constituent of influenza vaccines; or a history of
severe adverse reaction to a previous influenza vaccine.

- Known pregnancy or a positive urine beta-human chorionic gonadotropin test result
prior to first vaccination.

- Lactating or nursing women.