[A simple method for preparing autologous and homologous FITC/plasma protein conjugates to be used in vital microscopy].

The present paper describes a method for preparing a spectroscopically uniform conjugate of FITC with the respective plasma of the animal. This plasma is used for vital microscopy investigations. In the case of rabbit plasma, the FITC preparation consists of two protein components with molecular weights of 67 000 and 75 000 Daltons. Apart from these components, no further components could be found after filtration of the FITC preparation via a Sephadex G-75 column. The various fractions of the eluate from the Sephadex G-75 column showed an identical spectrum. It is suggested that the conjugate be purified by filtration over Sephadex G-75 columns for preparation of the FITC conjugate. The stability of the preparation at 37 degrees C is satisfactory. The decrease of the fluorescent emission is about 1% per hour in relation to the emission maximum at 540 nm.