Distribution, kinetics and immunoscintigraphy of 131-I labelled intact antifibrinogen-fibrin antibody (AbFbg) and its F(ab')2 fragment.

131-I-labelled anti fibrin-fibrinogen antibody (AbFbg) was compared with its F(ab')2 fragment in distribution studies and by immunoscintigraphy with a view to tumour visualization in tumour bearing rats. The distribution studies indicated that the intact antibody is more concentrated in tumour tissue than the F(ab')2 fragment. By 168h after injection, when tumour-to-tissue ratios were highest in the majority of tissues, the tumour concentration of intact antibody was 3 to 4 times that of the F(ab')2 fragment. The intact antibody is more suitable than the F(ab')2 fragment for tumour imaging especially in the abdominal region where the highest tumour-to tissue ratios were obtained with intact antibody in liver, spleen, intestines and kidneys.