In vitro determination of antigen quality: Biosensor analysis and fluorescence spectroscopy

Publication Type:

Journal Article


Modulation of the Immune Response to Vaccine Antigens, Volume 92, pp. 295-300 (1998)




diphtheria; toxin; toxoid; fluorescence; biosensor; diphtheria


We are probing the potential of two techniques to monitor the quality of antigens in vitro. Structural and conformational differences between diphtheria toxin and toroid are detected via biosensor analysis (BIA-core(TM)) and fluorescence spectrometry. With BIA-core the interaction kinetics between toxin and toroid and a monoclonal antibody were established. Tie fluorescence properties of both antigens were determined with respect to fluorescence intensity and emission maximum as a function of guanidinium hydrochloride concentration. In all cases clear differences were found between toxin and toroid. Antibody affinity of the toroid was lower compared with toxin, caused by lower binding and higher release rates. Fluorescence intensity of toroid was reduced by about 50 %. Toroid was less sensitive to guanidinium hydrochloride-induced denaturation, reflected in a diminished shift of the emission maximum.