Genetic and biochemical analysis of the a1 cell-surface antigen associated with human chromosome 11.

A highly versatile system for genetic, biochemical, and immunological analysis of human cell surface components has been developed using a human-Chinese hamster somatic cell hybrid containing chromosome 11 as its only human chromosome. This system lends itself to studies such as identification of human cell surface antigens and other genetic markers, regional gene mapping of these markers on chromosome 11, mutational analysis of these markers, and exploration of distribution of these antigens in normal and pathological human tissues. Genetic analysis of a1, one of the human antigens expressed by this hybrid, has been accomplished by subjecting a series of a1- variants to complementation analysis. These experiments have shown that the a1- variants behave in a recessive manner and that at least four genes, including three Chinese hamster genes, are needed for a1 antigen expression. Biochemical analysis has shown that a macroglycolipid isolated from human erythrocytes contains the a1 antigenic activity, so that genes coding for glycosyltransferases are required for its biosynthesis and may correspond to the complementation groups identified. The power of combined genetic, biochemical, and immunological approaches to understanding cell membrane molecules is demonstrated.