γ-irradiated BCG to Train Innate Immunity

Rationale: The live attenuated Bacillus Calmette-Guerin (BCG) vaccine protects against extrapulmonary infection with Mycobacterium tuberculosis and leprosy. It has been shown that vaccination with BCG also leads to nonspecific protective effects, e.g. reduced infant mortality as a result of less severe infections, stimulation of the immune system in patients with bladder cancer and higher cytokine production upon restimulation of macrophages with non-related infectious pathogens in vitro. However, because the live attenuated BCG vaccine cannot be used in immune compromised hosts, the investigators would like to determine whether similar protective non-specific effects can be induced by γ-irradiated BCG. Objective: To determine whether vaccination with γ-irradiated BCG results in a higher cytokine response by monocytes upon restimulation in vitro with infectious pathogens, compared to monocytes before the vaccination. Study design: Explorative intervention trial. Study population: Healthy volunteers, 18 - 55 years old. Intervention: Healthy volunteers will be vaccinated with γ-irradiated BCG vaccine. Main study parameters/endpoints: Blood will be drawn before and at two different time points after vaccination with BCG to perform restimulation of isolated cells in vitro and compare cytokine production. Nature and extent of the burden and risks associated with participation, benefit and group relatedness: There is no known direct benefit for the volunteers to participate in the trial. The risks are negligible. BCG vaccination can cause pain and scarring at the site of injection, just as fever and headache. Local hematoma formation can occur at the site of the blood drawing. This will be minimized by the blood collection by experienced persons.