Identification of different antigenic determinants within the synthetic multichain co-polymer poly(Tyr,Glu)-polyAla--polyLys as recognized by the chicken. I. Significance of the polyAla--polyLys backbone and identification of poly-D-alanine as the antigenic determinant in backbone-directed responses.

The multichain co-polymer poly(Tyr,Glu)-polyAla--polyLys, designated (T,G)-A--L, is normally thought to present only the poly(Tyr,Glu) sequences, designated (T,G), as antigenic determinants. Evidence is presented indicating that at least two different determinants in the (T,G)-A--L antigen are recognized by chickens. Studies in a partly inbred high-responder chicken strain reveal two major determinant systems: the (T,G) and the A--L in the (T,G)-A--L antigen. For one serum the antigenic determinant of the A--L backbone is shown to be a poly-D-alanine.