Material isolated from normal and variant human liver that immunologically crossreacts with alpha1-antitrypsin.

A material that strongly reacts with antibodies against alpha(1)-antitrypsin, but has little trypsin inhibitory capacity, has been isolated and purified to homogeneity from human liver. The molecular weight of the crossreacting material is about 18,000, which is significantly lower than that of serum alpha(1)-antitrypsin. The material isolated from the liver of a homozygous variant subject (ZZ) with alpha(1)-antitrypsin deficiency is readily distinguished by electrophoresis from the material extracted from a normal (MM) subject. The tissues from a heterozygous variant subject (MZ) contain the two components. The immunologically crossreacting material is presumably synthesized by the gene that codes for alpha(1)-antitrypsin.