The study is designed to assess the effect of ingestion of a probiotic on innate and adaptive host responses to rhinovirus infection.

The common cold is a ubiquitous illness of man that is associated with significant medical and socioeconomic consequences. Current treatments for the common cold that have proven efficacy are limited to pharmacologic agents that are directed at specific symptoms. These treatments- antihistamines, nasal decongestants and analgesics- have limited effectiveness, generally relieving the target symptom by 15-25% at the peak of activity, and are associated with bothersome side effects. There are no currently effective treatments for prevention of rhinovirus infections.

Probiotics have been defined by FAO/WHO as "Live microorganisms which when administered in adequate amount confer a health benefit on a host." The most common probiotics belong to Lactobacillus or Bifidobacterium genera. Bifidobacteria are natural human gut inhabitants that were discovered over a hundred years ago from the feces of breast-fed infants. The study product Bifidobacterium animalis subspecies (subsp.) lactis Bl-04 (Bl-04) has been genetically characterized as B. animalis subsp. lactis by 16S rRNA gene sequencing and full genome sequence comparison. Bl-04 has been deposited in the American Type Culture Collections safe deposit as SD5219.

This study will test the hypothesis that ingestion of a probiotic Bifidobacterium animalis subsp. lactis Bl-04 will alter the innate and adaptive host response to rhinovirus infection.

Inclusion Criteria:

AT ENROLLMENT:

• Subject must be 18-60 years of age.
• Subject must read and sign a copy of the approved Consent Form
• Female subjects must be using an effective birth control method.

INCLUSION CRITERIA AT DAY -28

• Subject must read and sign a copy of the approved Consent Form

AT CHALLENGE:

• Female subjects must be using an effective birth control method.
• Subject must have a serum neutralizing antibody titer of less than or equal to 1:4 to rhinovirus type 39

Exclusion Criteria:

AT ENROLLMENT:

• Current cancer diagnosis or immunosuppressive therapy in the last 6 months
• Any clinically significant abnormalities of the upper respiratory tract
• Any clinically significant acute or chronic respiratory illness
• Any clinically significant bleeding tendency by history
• Hypertension that requires treatment with antihypertensive medications
• History of angina or other clinically significant cardiac disease
• Any medical condition that in the opinion of the Principal Investigator is cause for exclusion from the study
• History of regular use (more than 3 days in 7) of tobacco products within the preceding two weeks
• History of drug or alcohol abuse in the 6 months preceding the study

EXCLUSION CRITERIA AT DAY -28

• Antibiotic use within 3 months prior to study start
• Female subjects with a positive urine pregnancy screen.
• History of use of probiotics in the preceding 2 weeks.

EXCLUSION CRITERIA AT CHALLENGE:

• Any upper respiratory infection or allergic rhinitis in the two weeks prior to the start of the study
• Any medical condition that in the opinion of the Principal Investigator is cause for exclusion from the study
• Use of any anti-inflammatory (steroids or NSAIDs) or cough/cold preparation in the two weeks prior to the study

Volunteers challenged with rhinovirus who met protocol definitions for analysis.

7 weeks