[Changes in isoagglutinin titers after high-voltage therapy with the large-field technic in Hodgkin's disease patients]. / Anderungen der Isoagglutinintiter nach Hochvolttherapie mit Grossfeldtechnik bei Patienten mit Morbus Hodgkin.

In 48 patients with Hodgkin's disease, the naturally occurring isoagglutinins anti A1, anti A2 and anti B were investigated and their titer determined before commencement of radiotherapy as well as after the end of radiotherapy, and in a proportion of the patients six and twelve months after the end of radiotherapy. Radiotherapy resulted in a highly significant fall in the isoagglutinin titer amounting on average to one titer level compared to the initial value before radiotherapy. After the end of radiotherapy, there was no further fall of the isoagglutinin titers, but a marked reduction of the isoagglutinin titers was still shown six and twelve months later. A long lasting reduction of serum immunoglobulins after radiotherapy in patients with Hodgkin's disease is known from earlier investigations; this applies in particular to IgM. Since the isoagglutinins mainly belong to the IgM fraction, our finding of persistent reduction of isoagglutinin titers after radiotherapy correlates with the known long-lasting reduction of serum IgM concentration.

Photochemical modifications of the tryptophan residues of wheat-germ agglutinin in the presence of trichloroethanol.

Trichloroethanol is an efficient quencher of indole fluorescence of model compounds and proteins [Eftink, M. R. and Ghiron, C. A. (1976) J. Phys. Chem. 80, 486--493]. At low quencher concentrations, the quenching follows the classical Stern-Volmer law. Bimolecular rate constants calculated from measured quenching constants and lifetimes are equal to 6 X 10(9) M-1s-1 and 1.2 X 10(9) M-1s-1 for N-acetyltrypotophanamide and wheat germ agglutinin, respectively. Upon ultraviolet irradiation in the presence of trichloroethanol, transformation of fluorescent tryptophan occurs, leading to a fluorescent photoproduct. This can be easily used as a method for the quantitative determination of fluorescent tryptophan residues in proteins. In good agreement with previous results, two fluorescent tryptophan residues per polypeptide chain are found in wheat germ agglutinin. Concomitantly with the photochemical reactions, the hemagglutinating protein activity and its affinity constant towards chitin oligomers are reduced. A probable location of tryptophan residues in the binding sites of wheat germ agglutinin is proposed.