Antigenicity and tolerance of some synthetic polypeptides related to collagen

Guinea-pigs immunized with poly-L-proline, poly-L-proline—glycine or poly-L-proline—glycine—acetyl-hydroxy-L-proline develop antibodies which appear to be exclusively directed against determinants composed of sequences of proline.

(2) All three antigens also induce delayed hypersensitivity but the determinants involved include both glycine- and acetyl-hydroxyproline when the antigen is poly-proline—glycine—acetyl-hydroxyproline and glycine when the antigen is poly-proline—glycine.

(3) The administration of either polyproline or poly-proline—glycine in incomplete adjuvant produces a state of tolerance as revealed by subsequent injection of the peptides with Freund's complete adjuvant.

(4) Tolerance induced with poly-proline cannot be broken by immunization with poly-proline—glycine with regard to circulating antibody but is broken with regard to delayed hypersensitivity.