Respiratory burst as a biomarker for stress responses

A module for the detection of immunotoxic events within the test system Triple-Lux to be used during spaceflights was developed. It is based on the production of reactive oxygen species within the respiratory burst during phagocytosis or after stimulation of the phagocytes with phorbol 12-myristate 13-acetate (PMA). For this purpose, luminol-dependent chemiluminescence was measured. The assays were carried out with polymorphonuclear leukocytes purified from sheep peripheral blood. The influence of hydrocortisone and Cd ²⁺ on the respiratory burst in polymorphonuclear leukocytes was assayed. Hydrocortisone in concentrations between 10^-4 and 10 ^-9 mol/liter showed an immunostimulating effect after PMA treatment. An immunosuppressive effect was observed for Cd²⁺ in concentrations between 10^-4 and 10^-7 mol/liter. Cryoconservation, which has often been critical for primary cells, can be accomplished without any subsequent loss of function by freezing the cells in dimethyl sulfoxide-containing medium.