The evaluation of TIP is based on the differentiated HL-60 cellline,
which, upon exposure to microbial compounds, reacts by
producing reactive oxygen species (ROS). Human airways and lung
alveoli contain small number of granulocytes. In the human body
the pulmonary vasculature is the largest reservoir of granulocytes.
The pulmonary vasculature can distribute the granulocytes rapidly
and thus respond against pathogens [53]. Although the isolated granulocytes are short-lived [60], the production of ROS of granulocytes
can represent a readout for microbial exposure. ROS can be
quantified by a luminol dependent chemiluminometric assay.