Immunochemical Study of Antigenic Specificity in Delayed Hypersensitivity Ix. Delayed Hypersensitivity to Polytyrosine-azobenzenearsonate and Its Suppression by Haptens* by Sidney Leskowitz, Ph.d

Studies of immunologic specificity in delayed hypersensitivity to haptenprotein conjugates have thus far been interpreted as demonstrating that the carrier protein contributes an important component to the specificity of the reaction. I t has been suggested, for example (1), that delayed hypersensitivity represents a "broadened" specificity which becomes narrowed to more dearly defined groupings during the process of antibody production. More recently, Benacerraf and Gell (2, 3) have stated that the so-called "carrier specificity" represented an appreciable overlap beyond the hapten onto the adjacent protein molecule, suggesting that the size of the determinant area was larger or that the interactive forces were stronger in the delayed reaction than were those involved in reaction with conventional antibody. In an attempt to analyze further the nature of this apparent "carrier protein" specificity, studies were carried out with conjugates made with oxidized or reduced proteins, which differed from the native proteins only in "tertiary" or folded structure but retained the same "primary" or amino acid sequence (4). Results obtained with these materials suggested strongly that specificity in delayed hypersensitivity to hapten-protein conjugate was to a large extent influenced by amino acid sequence and was also characterized by considerable heterogeneity, probably related to multiple antigenic determinants produced by differences of sequence in various proteins. Therefore, it was decided to use as a more homogeneous carrier material for immunization a polymer composed of a single amino acid. The present article is concerned with the results obtained using diazotized arsanilic acid conjugated to polytyrosine as the antigen.