Study of the Ag(z) Factor

Abstract

THE existence of a genetically determined β-lipoprotein polymorphism in human serum was detected by Allison and Blumberg¹ and Blumberg et al.², employing a precipitating antibody which was present in the serum of a repeatedly transfused patient (C. de B.) The same antiserum was investigated by Hirschfeld et al.³ and was shown to contain at least three different anti-Ag antibodies against β-lipoprotein factors which were called Ag(a₁), Ag(x), and Ag(z). Data on the genetics of the Ag(x) and Ag(a₁) factors were reported by different authors^4–6 who used monospecific anti-Ag(x) and anti-Ag(a₁) sera. Only one other serum (C352) was found to possess anti-Ag(z) but it also had other anti-Ag specificities⁷. At present, the only source of anti-Ag(z) consists of serum from C. de B. absorbed with an Ag(x+a₁+z−) serum. The complicating fact is that C. de B. seems to possess a fourth antibody⁸, so that absorption with Ag(x+a₁+z−) sera may be unsuccessful in producing specific anti-Ag(z) antiserum. It can therefore be used in immunogenetic studies only with considerable caution.