The Fate in Rabbits of Intravenously Injected I131-Iodoovalbumin

Abstract

The fate of the trichloracetic acid-precipitable radioactivity of I¹³¹-iodoovalbumin in intravenously injected rabbits was investigated on both the gross organ level and the subcellular level. The determinant groups of the iodoproteins appear to be stored in the tissues for an indefinite length of time. After their injection they are concentrated briefly in the microsomal fraction of the liver and spleen. This is followed by a long term concentration in the mitochondrial fraction. The administered dosage did not seem to influence the pattern of intracellular distribution of radioactivity up to 24 hours following an injection. Previous intravenous injections of non-radioactive iodoovalbumin did not greatly alter the organ deposition or distribution among the liver fractions of a final labeled injection. The experimental results are consistent with the concept that antibody formation is a cytoplasmic phenomenon occurring in the presence of the antigen. The antigen involved in antibody formation is most likely concentrated in the mitochondria.