Delayed hypersensitivity in guinea pigs was produced by immunization. with a conjugate prepared by coupling diazotized
arsanilic acid to
polytyrosine. The resulting sensitivity could be demonstrated by skin test with conjugates prepared from a wide variety of
tyrosine-containing
proteins. Definite but smaller degrees of sensitivity could be induced with conjugates of
proteins containing little or no
tyrosine. The apparent absence of carrier-specificity is considered to be due to the narrowed range of immunologic response produced by immunization with
polytyrosine-azobenzenearsonate.
Injections of the
hapten N-acetyltyrosine-azobenzenearsonate was found to suppress completely the delayed reaction attributable to the
tyrosine-azobenzenearsonate group. The same
hapten was only slightly effective in suppressing reactions in guinea pigs immunized with guinea pig
serum albumin-azobenzenearsonate, suggesting that a broader range of specificities is involved with such
antigens. Confirmation of such increased range of specificity attributable to
antigenic determinants contributed by the
carrier protein was obtained by desensitization studies with
N-acetyltyrosine-azobenzenearsonate and guinea pig
serum albumin-azobenzoate. While separately these materials produced only a slight decrease in skin reactivity to guinea pig
serum albumin-azobenzenearsonate, the combination was found to give almost complete suppression.