Highly Specific Lung Localizing Antibodies

Abstract

Rabbit antibodies against rat lung or kidney were labeled with ¹²⁵I and injected into rats. The distribution of the antibodies on cellular fractions obtained by differential centrifugation was different for the lungs and kidneys. In lung, the antibody was found in the microsome fraction. In contrast, the antibodies localized in kidneys were associated mostly with a fraction sedimentable at 700 RCF. Both anti-lung and anti-kidney antibodies behaved very similarly in this respect. Antibodies associated with cellular fractions of lungs and kidneys were eluted and the localizing properties of the eluates were determined. The microsome fraction of lung gave the eluate which showed the highest as well as the most preferential localization in lungs. On the other hand, the low speed sediment fraction of kidney gave the eluate which showed the highest as well as the most preferential localization in kidneys. Exhaustive absorption of in vivo purified anti-lung antibodies with sediments of kidney and liver revealed that 20% of the antibodies were lung specific localizing antibodies. A smaller proportion of kidney specific localizing antibody was isolated from an anti-kidney antibody preparation.