Human Innate Immune Responses To Mycobacterial Aerodigestive Tract Infection
Human Innate Immune Responses To Mycobacterial Aerodigestive Tract Infection
The approach we will use is to employ measurement of the activation of white blood cells, to
 look at patterns of responses during a controlled infection of the gut with Mycobacterium
 bovis. M. bovis can be conveniently obtained in a safe and pure form as an oral vaccine. By
 giving three challenges of M bovis to the gut, we will simulate repeated gut infections with
 this organism. We can then compare the activation of cells in the blood to the immune
 responses seen after each challenge, to determine whether the non-specific defences of the
 gut can block each subsequent infection.
The approach we will use is to employ immune readouts and genomics to look at patterns of
 responses during a controlled infectious challenge of the human gut.

 Genomics uses 'Affymetrix' gene arrays, and other techniques to determine the profile of gene
 expression. When a gene is 'switched on' it makes mRNA that the body uses as a template to
 make proteins. We will extract all the mRNA from white blood cells before, during and after
 an infection. The gene chips have hundreds or thousands of mini-sensors that can measure how
 much mRNA from any particular gene is present in the sample. Thus we can begin to see which
 genes are switch on or off, or unaffected, inside white blood cells during the stages of a
 developing innate immune response. This allows us to monitor the body's response to an
 infection and to see which families of genes are important at the different stages of gut
 infection.

 The BCG vaccine is derived from Mycobacterium bovis (the full name of the organism is
 Mycobacterium bovis Baccille Calmette Guérin). In this study we propose to use an oral BCG
 preparation, produced as a prophylactic and therapeutic oral vaccine, as a safe model for
 natural gut infection with pathogenic Mycobacterium bovis. The cell wall of mycobacteria such
 as BCG is a powerful immune adjuvant (an adjuvant is a substance that enhances an immune
 response) as the lipids, sugars and proteins in the cell wall interact strongly with the
 molecules of the innate immune system. It therefore provides a safe but highly effective way
 to stimulate innate immunity under 'natural' conditions of gut infection. This first model
 has been selected as it reflects a 'real world' high priority area of disease prevention,
 while having a high level of safety and reproducibility in the oral BCG model.

 By carefully delivering oral BCG challenges to healthy volunteers under controlled
 conditions, we can reduce the noise and background activity in the proteomic and genomic
 assays we will use to profile the developing innate immune response. We can check that the
 BCG has indeed colonised and 'infected' the subject by measuring the specific adaptive T cell
 and antibody responses using sensitive assays we have developed in previous studies to detect
 these immune responses. This is a critical aspect of the study: if we detect the BCG-specific
 T cell responses we can be assured that the 'infection' has taken place, and so can interpret
 the profiles we see in the immunology and genomics.

 If we see an immune response we can relate any innate immune activation to colonisation with
 BCG. In contrast, even if we see no immune responses, but can be sure that the vaccine was
 delivered properly in a viable formulation (which we will do by adhering to strict Good
 Clinical Practice) then we can look at features in the genomic and proteomic profiles in the
 baseline measurements before infection that may predict the failure of the organisms to
 infect.

 By collecting data of other events such as intercurrent illnesses, or other adverse events we
 can also determine whether changes in the proteomic or gene expression profiles are indeed
 due to the model infection, or extraneous events. This preliminary study will enable us to
 refine expensive techniques, protocols and assays to let us focus in more detail in
 subsequent studies

 This study will be conducted according to the Standard Operating Procedures (SOPs) of the St
 George's Vaccine Institute. Up to 10 subjects will be included in this study. The study will
 consist of a pre-study screening visit and 23 visits over a period of 12 month at the times
 indicated in the schedule for investigation.
Inclusion Criteria:

 -  Adult volunteers, 18 to 45 years of age, who sign an informed consent form following a
 detailed explanation of participation in the protocol.

 -  Volunteers who are in good health as determined by medical history, physical
 examination and clinical judgement.

 -  Volunteers who will be available for the duration of the study.

 -  Volunteers willing and able to give written informed consent.

 Exclusion Criteria:

 -  Volunteers who are contraindicated for BCG vaccination according to the Manufacturer's
 Data Sheet.

 -  Individuals who have hypersensitivity to any component of the vaccine used in this
 study.

 -  Individuals who have severe or multiple allergies, including to drugs or
 pharmaceutical agents.

 -  Volunteers who are receiving drug treatment for, or who have a significant history of,
 cardiological or respiratory disease. Volunteers who are suffering from severe
 cardio-respiratory disease, including hypertension, or an active neurological
 disorder.

 -  Individuals found to be HIV antibody positive at screening, or with a known impairment
 of immune function, or those receiving immunosuppressive therapy, including regular
 inhaled steroids. Intermittent steroid use (less than twice per month in the preceding
 3 months) is acceptable.

 -  Individuals with acute infections (including fever >38°C).

 -  Women who are pregnant or lactating.

 -  Women capable of becoming pregnant who do not agree to have pregnancy testing before
 immunisation, and/or who do not agree to take effective contraception for the duration
 of the study period.

 -  Individuals with a current problem with substance abuse or with a history of substance
 abuse, which, in the opinion of the investigator, might interfere with participation
 in the study.

 -  Individuals with any condition, which, in the opinion of the investigator, might
 interfere with the evaluation with the study objectives.

 -  Individuals who have received an investigational agent within 30 days prior to entry,
 or been in any other study in the last 6 months.

 -  Individuals who are planning to leave the area of the study site prior to the end of
 the study period, or who are likely not to complete the study.