Genetically determined differences in the response of alpha1-antitrypsin levels in human serum to typhoid vaccine

Summary Normal individuals and those homozygous and heterozygous for the gene which determines deficiency in serum ₁-antitrypsin (₁-at) were given an intravenous injection of typhoid vaccine. Following this injection the trypsin-inhibiting capacity of serum and the concentration of ₁-at increases markedly in normal individuals. Heterozygotes for the deficiency gene have an elevation of ₁-at and trypsin-inhibiting capacity of their serum but reach only 50 percent of the levels reached by homozygotes for the common gene (normal individuals). Their values are however temporarily in the range of normal men not given typhoid vaccine. Homozygotes for the deficiency gene show only a small elevation of ₁-at under these conditions. These findings demonstrate that (1) the increase in trypsin-inhibiting capacity of serum after an injection of typhoid vaccine is largely due to the elevation of the ₁-at concentration, and (2) the ₁-at deficiency gene inhibits the quantitative response of the ₁-at to such a stimulus.Supported in part by USPHS grant HE-06285 from the National Heart Institute.Some of these studies were carried out in the General Clinical Research Center Ward, U. C., FR-79, supported by the Division of Research Facilities and Resources, U.S. Public Health Service.