Evaluation of Safety and Tolerability of Tyrosine Adsorbed Ragweed Pollen Allergoid With MPL (Monophosphoryl Lipid A)

Inclusion Criteria: * Non-smoker and not using any nicotine products * Negative skin prick test with a standard panel of marker allergen extracts (including ragweed allergen extract) * Specific IgE for ragweed with class = 0 * No clinical history of IgE-mediated allergic diseases * Subject agrees not to use any medication or herbal products during the study * Males or non-pregnant, non-lactating females who are post-menopausal, naturally or surgically sterile, or who agree to use effective contraceptive methods throughout the course of the study. * Subjects who are normally active and otherwise judged to be in good health on the basis of medical history, physical examination, routine laboratory tests and an infection screen * Subjects must be willing and able to attend required study visits. * Subjects must be able to follow instructions. Exclusion Criteria: * Clinical history or presence of acute or subacute atopic dermatitis, chronic dermatitis, urticaria factitia, or urticaria due to physical/chemical influence. * Clinical history or presence of diabetes, cancer or any clinically significant cardiac, respiratory, metabolic, renal, hepatic, gastrointestinal, dermatologic, venereal, hematologic, neurologic or psychiatric diseases or disorders. * Any clinically significant (as determined by the Investigator) abnormal laboratory value at Visit 1 * Clinical history of auto-immune diseases or rheumatoid diseases. * Contraindication to adrenaline * History of asthma * Subject has used any prescription medications within 14 days or over-the-counter medications, including herbal products, within 2 days prior to Screening or will likely use any medication(s) or listed product(s) during the study. * Subject has disorder of tyrosine metabolism * Subject with diseases with a pathogenesis interfering with the immune response and who has received medication which could influence the results of this study * Subject has acute or chronic infection * Clinical history of anaphylaxis * Clinical history of angioedema * Clinical history of hypersensitivity to the excipients of the study medication * History of immunotherapy with ragweed allergen extracts * Current therapy with ß-blockers * Currently receiving anti-allergy medication or other drugs with an antihistaminic activity * Subject has a positive screen for cotinine or drugs of abuse at Visit 1 * Subject has a positive saliva alcohol test at Visit 1 * Subject participated in a clinical trial with a new chemical substance within the last 12 months * Subject cannot communicate reliably with the Investigator or is not likely to cooperate with the requirements of the study * Subject is pregnant or lactating * Clinically relevant abnormal vital signs or respiratory rate at the Screening Visit * Subject received treatment with a preparation containing MPL® during the past 12 months.